black holes

Needgmat wrote:Scientists have recently found evidence that black holes- regions of space in which matter is so concentrated and the pull of gravity so powerful that nothing, not even light, can emerge from them- probably exist at the core of nearly all galaxies and the mass of each black hole is proportional to its host galaxy.

A) exist at the core of nearly all galaxies and the mass of each black hole is proportional to

B) exist at the core of nearly all galaxies and that the mass of each black hole is proportional to that of

C) exist at the core of nearly all galaxies, and that the mass of each black hole is proportional to

D) exists at the core of nearly all galaxies, and that the mass of each black hole is proportional to that of

E) exists at the core of nearly all galaxies and the mass of each black hole is proportional to that of


OAB


Many thanks in advance.

Kavin

First, ignore the long modifier set off by the dashes. We're left with the following decision:

Scientists have recently found evidence that black holes probably exist/exists
Black holes = plural, so we want "black holes exist

Eliminate D and E.

Now note the comparison in A and C: the mass of each black hole is proportional to its host galaxy. The writer doesn't want to communicate that the mass of a black hole is proportional to a galaxy but to the mass of a galaxy. Eliminate A and C.

We're left with B. The mass of each black hole is proportional to that [that = the mass] of its host galaxy.