First multiply C by F by multiplying each row in C by each column in F:
12 * -2 + 0*0 + 1.5*2 12*0 + 0*8 + 1.5*1
1*-2 -6*0 +7.2 1*0-6*8 +7*1
to get a matrix of:
-21 1.5
12 -41
Now subtract that matrix from B:
2- -21 = 2+21 = 23
8 - 1.5 = 6.5
0.6 - 12 = -11.4
3 - -41 = 3+41 = 44
So you have:
23 6.5
-11.4 44
Which makes C the correct answer.