I am between A and D. probably A.
get rid off "whom" because "who has" is correct and "whom has" is not.

Agree with your explanation. A is indeed the correct answer.

According to Wikipedia:

Rules for determining who vs. whom
To determine whether who or whom should be used in a sentence, recast the sentence in non-interrogative form and determine whether you would use he or she (nominatives) or him or her (accusatives and datives) instead of who or whom. For this sentence, this yields:

correct -- I shall say she is calling.
incorrect -- I shall say her is calling.
Since the latter sentence is a solecism, this sentence calls for who rather than whom. But:

Whom did you call?

yields:

incorrect -- You called she.
correct -- You called her.
indicating that whom is appropriate for this question.

Basically, whom is used whenever there is no verb to be in an inflected form referring to it. Thus:

He was the man whom we later learnt to be a constable.
He was the man who we later learnt was a constable.
He was the man whom we thought a constable.
Whom will you give this? (will refers to you, not whom) (this sentence may sound somewhat old fashioned because in it, whom directly represents the dative case; perhaps the following forms might be preferred: "Whom will you give this to?", or "To whom will you give this?")
Who will come?
Also, whom is the form used whenever there are prepositions involved, since these always take the dative or accusative case:

To whom have you been talking?
For whom have you taken these marvellous photographs?
With whom are you going to the cinema?
We have been discussing plans with them, of whom we have grown rather fond these days.
We have been discussing plans with them, whom we have grown rather fond of these days.
The same rule applies to declined pronouns whomever and whomsoever.

Especially when placing the preposition at the end of a sentence, whom is usually replaced with who, even in formal situations, hence including written, English:

To whom do I owe this? = Whom do I owe this to? = Whom do I owe this?
Who do I owe this to?

C

past participle tense? and correct usage of objective pronoun "whom", for Virgin Mary.

I go for D.

the last sentence means it should not use past perfect, as the vision continues to the ensuing years later.

From Amazon: http://www.amazon.com/Visions-Children- ... 031218204X


In June 1981, six teenagers in the village of Medjugorje, Yugoslavia (now Bosnia and Herzogovina), claimed to have had visions of the Virgin Mary, whom they say has continued to appear to them over the ensuing 10 years

Hay Guys may be this might help u

Who vs. Whom
Students often encounter difficulty in deciding whether to use who or whom. Two
sentence patterns in particular lead to confusion with these words: when they begin a
question and when they introduce a dependent clause. Deciding on the appropriate
pronoun requires grammatical analysis, noting the differences between subjective
personal pronouns (pronouns that perform an action) and objective personal pronouns
(pronouns that receive an action). Who is a subjective pronoun; whom is objective.
1. Introduction of a question:
When the answer to the question begins with a subjective personal pronoun (e.g.
he/she/they), use who.
Who is the best pitcher on the team? He is the best pitcher on the team. [He is subjective; therefore, who
is correct.]
When the answer to the question is an objective personal pronoun (e.g. her/him/them),
use whom.
For whom did you vote? I voted for her. [Her is objective; therefore, whom is correct.]
2. Introduction of a Dependent Clause
When the pronoun acts as the subject of the clause, use who.
He is a wonderful man who is destined for great things. [Who is the subject of the clause “who is destined
for great things” -– or -- (S)he is destined for great things.]
When the pronoun acts as the object of the clause, use whom.
The man at the door was not whom she had expected. [Whom is the object of the clause “whom she had
expected” -- or -- she had expected him/her.]