Bunuel
The company has built a new tool — being tested in Europe and slated to be rolled out more widely this year in a variety of different countries —
letting people see the different ads placed by political pages, which is a move meant to address influence campaigns like those seen in the 2016 U.S. presidential election.
(A) letting people see the different ads placed by political pages, which is a move
(B) that let people see the different ads being placed by political pages, and it is a move
(C) that let people see the different ads placed by political pages, which is a move
(D) that lets people see the different ads being placed by political pages, a move
(E) that lets people see the different ads placed by political pages and is a move
VERITAS PREP OFFICIAL SOLUTION:
There are two important decision points in this problem: the subject-verb agreement choice between “let” and “lets” and the different structural/modifier choices at the end of each answer. Starting with the easier subject-verb agreement choice, you can eliminate (B) and (C) as the clause “that let…” is modifying “a new tool,” which is singular. It must be “a new tool that lets….”
In comparing the remaining three choices, you should hone in on the “which” clause at the end of (A). There is no singular noun nearby for that clause to logically modify, so you know it is incorrect and can be confidently eliminated. (D) and (E) are identical but for two differences: (D) has “being placed” instead of “placed” but the important decision point is the one between “pages, a move” in (D) and “pages and is a move” in (E). For (E), the use of a conjunction creates the following illogical sentence: “the company has built a new tool and is a move…” The company cannot be “a move” so this structure is clearly incorrect.
For (D), the appositive modifier added to the end of the sentence with a comma logically modifies the entire preceding clause and the use of “being” is preferred with the past participle, as it emphasizes that they get to see the action of ads being placed. The correct answer is (D).