a and c i think
the blue circle is all the people who had brothers one name was in the blue circle so one person had a brother but the in between part of the too circles are who had both a brother and a sister so the is one name in the between purple so you count that one to for brother and for sisters
there were 2 people that had brother
and four people that had sisters
and one that had both
The answer would be 2x^2+2x-24
using foil, you would multiply together x & x, x & 6, -4 & x, and -4 & 6, then add them together.