What other compromise was undone by the compromise of 1850

yup! you are correct it is b.

the correct answer is: (1) affected by gerrymandering; (2) not affected by gerrymandering.

gerrymandering is known as a practice that intends to establish a some kind of political advantage for a particular party or group. to do this district boundaries are manipulated. the new resulting district is named a gerrymandering.

in other words, what gerrymandering does is to draw the boundaries of electoral districts trying to benefit the party who is doing it. sometimes, the party controlling the legislature will redraw it so they can maximize the number of districts they are likely to control.