In most major metropolitan areas, the number of hate crimes

[BTGmoderatorDC]

In most major metropolitan areas, the number of hate crimes per capita is significantly lower in neighborhoods in which the population is racially mixed, that is, no more than one third of the area's inhabitants belong to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone who he regards as a neighbor.

A. that is, no more than one third of the area's inhabitants belong to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone who he regards as a neighbor
B. that is, no more than one third of the area's inhabitants belong to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone whom he regards as a neighbor
C. that is, no more than one third of the area's inhabitants belongs to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone whom he regards as a neighbor
D. that is, no more than one third of the area's inhabitants belongs to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone who he regards as a neighbor
E. that is, no more than one third of the area's inhabitants belongs to the same ethnic group; it is theorized that a person is less likely to commit a hate crime against someone whom he regards to be a neighbor

OA C

Source: Princeton Review

[deloitte247]

The part of this sentence that is underlined consist of two basically errors a subject/verb disagreement and a misused pronoun. The subject of the clause is One-Third, which is singular, so it requires the singular verb belongs. Also, Who should be replaced with whom

Option A - Incorrect
"Belong" should be replaced with "belongs" for it to agree with One-Third (singular) and "who" should be "whom".

Option B - Incorrect
This option contains the right pronoun but does not make use of the subject/verb disagreement in "belong". This makes this option incorrect.

Option C - Correct
This option contains the correct subject-verb agreement. The correct verb belongs link up with the correct pronoun whom.

Option D - Incorrect
The use of "belongs" tends to make this option correct, but "who" is not the right pronoun to be used.

Option E - Incorrect
Meanwhile, this choice corrects the subject/verb disagreement and the pronoun misused in this question. However, it brings in anew error (regards ... to be); it should be (regards ... as ).