Official Explanation by Mikemcgarry on his blog :
Split #1: SV Agreement. The subject of the second clause, “some”, refers back to the “the university’s faculty”. This is a collective noun. While there are many faculty members, the faculty is singular, and “all of the faculty” or “some of the faculty” must be singular as well. Notice the singular verb in the first half of the sentence. The second must be singular as well. Choices (A) & (C) & (E) are incorrect.

Split #2a: idiom with “willing”. The adjective “willing” take an infinitive: willing to do X. The structure “willing for doing X” is never correct. Choices (D) & (E) make this mistake.

Split #2b: idiom with “extend”. When we give someone a welcome, we say that we extend the welcome to him. Use of “for” in this context is never correct. Choices (A) & (E) make this mistake.

For all these reasons, (B) is the only possible answer.
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I understand FACULTY is Singular...but doesn't the word 'SOME' means more than 1 hence ARE should be used?

All of the university’s faculty is appalled by the decision to hire as university president the senator censured for influence peddling, but some are willing to extend for him a civil welcome.

A. are willing to extend for

B. is willing to extend to

C. are willing to extend to

D. is willing for extending to

E. are willing for extending for

C is the answer. 'Some' is Plural. Please update that.

Dear,

It's NOT compulsory that SOME is always PLURAL....
1. Some of the money WAS stolen
2. Some of the documents WERE stolen.

Which of the above sentence is correct.....? BOTH ARE CORRECT

So, SOME could be SINGULAR or PLURAL, depending upon usage



Look at two sentences
ALL of the university's faculty IS appalled - Correct
&
SOME ARE willing - Incorrect since faculty is treated singular
or
SOME of the university's facult IS willing - CORRECT

So, options A,C,E are out.

Correct idiomatic usage is Willing TO EXTEND or EXTEND TO.

Hence Answer B

Some can be either Singular or Plural depending on the noun it refers to. In this context "some" is referring to "university’s faculty". The non-underline portion of the sentence "university’s faculty is" use "is" clearly gives us a clue that it should be considered singular. Hence the answer "B"

SANAM - Some, Any, None, All, More/Most can be singular or plural depending on the context of the sentence.
In this case, some refers back to the singular 'faculty'.

Although "faculty" is a collective noun, I just don't buy the usage here. We need some flexibility, and we shouldn't let a so-called rule force us into a construction that doesn't make sense. The article linked below provides a good tip. To see if a collective noun such as faculty should be used as a plural, see if it makes sense to add "members" to the word.

https://languagetips.wordpress.com/2012 ... -nauseous/
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Official Explanation

Split #1: SV Agreement. There is a subtle SVA issue here. If we are talking about the group of individuals, when do we use the singular verb for the group and when do we use the plural verb for the separate individuals? If whole group, more or less, is acting as a whole in some way, we emphasize the group and use the singular verb: for example, when we discuss what "most" are doing in the first half of the sentence, we use a singular verb. By contrast, if we are discussing how some members of the group are diverging from others and acting in individual ways, then we emphasize the individuals and use the plural verb. For the verb in the underlined section, the plural verb would be preferable. Choices (C) & (D) make a less than optimal choice in choosing the singular verb.

Split #2a: idiom with “willing”. The adjective “willing” take an infinitive: willing to do X. The structure “willing for doing X” is never correct. Choices (D) & (E) make this mistake.

Split #2b: idiom with “extend”. When we give someone a welcome, we say that we extend the welcome to him. Use of “for” in this context is never correct. Choices (A) & (C) & (E) make this mistake.

For all these reasons, (B) is the only possible answer.

FAQ: Can you talk a little more about when to use "is" and "are" for these collective nouns? I'm confused.

Sure! Dealing with agreement with collective nouns can be subtle, because you have to tap into the MEANING of the sentence to make the right call. Specifically,

if the sentence stresses the uniformity or 'togetherness' of the group, then use the singular;
if the sentence stresses individual actions (perhaps grouped together, but still regarded as clearly individual), then go with the plural.
If you are completely in doubt, err on the side of going for the singular option. This is not foolproof, but we find that most often—especially on the GMAT—the bias is toward the singular.
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I am really finding it hard to accept how B fits. This question has "some" serious "issues".

GMATNinja:
Can you please shed some light on this.

I see that this is a case where 'some' can be interpreted as singular.
But, if I am reading this sentence with 'is' after 'some', something does not feel right.

Specially because when we say 'some', the concept of collective noun, in my mind gets broken. Now there are some people who are willing and others who aren't.

Also, I do realize there is ellipsis going on here. Does that make any difference? I can't digest 'is' with 'some' the way it's used here. I get that those two go together, but not here.

Classic case of testing for rules where it doesn't make any sense. Sorry but this is not a GMAT 700 level question.