The temperature dropped suddenly last night which will mean that the

OFFICIAL EXPLANATION






• OVERVIEW

→ Meaning?
The temperature dropped suddenly last night; the resulting frost will kill new plants that are emerging from the soil.

→ Things to remember:
(1) which is a relative pronoun.
A pronoun must refer to a noun—not a previous clause, not an idea, but rather, a stated noun.
Out of hundreds of official questions, I know of only one in which the word which seems to be allowed to stand for the preceding clause that did not contain a noun to match with which. (And I cannot find that one example at the moment.)

(2) this is not a standalone pronoun 99.9 percent of the time.
This can be an adjective (determiner): this red plate; this kind of felony; this smaller dog, not that larger one.
But in formal speech and writing, the word this cannot be a standalone pronoun and cannot refer to a previous clause or the idea in a previous clause.

Very few rules are ironclad, but the one I just mentioned holds almost without exception.
That said, in OG 2020, for the first time that I know of, the correct answer contained a standalone "this" that referred to an entire clause.
That official question is here.
It is the only question of its kind of which I am aware.

→ If you see a strange-looking noun phrase surrounded by commas in the middle of a sentence, you are probably looking at an appositive.
Purdue OWL is an excellent writing and grammar source.
This article, here explains appositives and takes three—three —minutes to read.
Why am I talking about appositives? Option B contains one. (Hint: it starts with "an event.")

• Split #1: The case of the missing antecedent or rogue pronoun

In option A, the pronoun which does not have a noun antecedent.
The word which is improperly trying to refer to the entire preceding clause, the temperature dropped suddenly last night.
That clause, however, contains no noun that could act as an antecedent for which.
As a matter of logic, which cannot be referring to the nouns temperature or night.
No noun referent? No antecedent. Wrong.
Eliminate A

In option C, the word this tries improperly to accomplish what which improperly tried to accomplish in option A.
If option C had used the phrase "this event," the option would be on more solid ground, though the option is wordy and stylistically inferior to the correct answer.
Eliminate C

• Split #2: misplaced modifier

Noun modifiers should be placed as close as possible to the nouns they modify.
In option E, the phrase emerging from the soil seems tacked lazily onto the end of the sentence and is too far away from its target, the word shoots.
In fact, because emerging . . . looks like an appositive, it seems to refer to frost.
Frost does not emerge from soil.

Participle modifiers (verbING modifiers) can and do modify the subject of the previous clause, but in this case the modifier is too essential to be placed this far from its noun, and the modifier's distance from the noun is too jarring.

The modifier emerging from the soil theoretically could modify shoots.
(If you get too literal with the participle rule, you will not see that the placement of this modifier creates an abysmal sentence.)
That modifier, though, is better placed right next to its noun, and its placement in option E not only makes for strange separation from the noun but also stultifies the sentence.
If you are not sure, hold the option and look for a better one.
Eliminate E

Split #3: Option B or option D?

Option D is better than option B.
The meaning in option D, which explicitly mentions "resulting," is clearer than that in option B, which attenuates the connection between event and "will kill."
In formal writing, we do not very often speak of an event meaning something.
True, the word mean can connote "result" or "consequence."
That usage is uncommon though not unheard of. (See Oxford online dictionary, #3, in this dictionary entry.

Option D is
-- more concise (many fewer words and streamlined phrasing);
-- more precise (resulting frost is clearer and crisper than an event that will mean that)
-- and more "punchy" than is option B.
In option D, the resulting frost will kill connotes something drastic; "will kill" is drastic.
By contrast, in option B, we must wade through all the words I have stricken here:
an event that will mean that the frost will kill.

Option B is not as good as option D.
Eliminate B.

The correct answer is D.

COMMENTS

Mohsengho , welcome to SC Butler.
Aspirants have a standing invitation to post on Butler.

I am also glad to see posters whom I haven't seen in a while.

Here comes the broken record, instigated by three scholarly articles I read yesterday that confirm all the other studies:
The best way to learn something is to teach it.

Want to get better at Verbal?
Post.
Explain.
(And read, though reading is more passive than teaching is.)

winterschool , I am bumping you to Best Community Reply.

Most of these posters address issues I do not or do not address in depth.
Good work.