A middleweight black hole weighs in at roughly 500 solar mas

[BTGmoderatorDC]

A middleweight black hole weighs in at roughly 500 solar masses, hundreds of times more massive than the lightweight black holes produced by the collapse of individual stars, but thousands or even millions of times less in its mass as the heavyweight giants that lurk in the centers of galaxies.

(A) thousands or even millions of times less in its mass as
(B) it is thousands or even millions of times less massive as
(C) thousands or even millions of times less massive than
(D) yet it is thousands or even millions times less massive than
(E) yet it is thousands or even millions of times less in its mass than

OA C

Source: GMAT Prep

[ceilidh.erickson]

This question is testing simple parallelism.

The correct parallel structure (logically and grammatically) is:
1. hundreds of times more massive than ___
2. but thousands or even millions of times less massive than ____

(A) thousands or even millions of times less in its mass as
- "less in its mass" --> not idiomatic
- "less" requires "than," not "as"

(B) it is thousands or even millions of times less massive as
- "less" requires "than," not "as"

(C) thousands or even millions of times less massive than
- correct

(D) yet it is thousands or even millions times less massive than
- "but yet" is redundant

(E) yet it is thousands or even millions of times less in its mass than
- "but yet" is redundant
- "less in its mass" --> not idiomatic

The answer is C.