Which expression equals 24? a (2 + 4)(3) and b (4 × 2)(3) then c (4 + 3) - 2 and d (4 - 2) + 3 ?

Simple, just try the equations until you get the number you're looking for:

A.) (2+4)(3)
       (6)(3)= 18
A.)18

B.) (4*2)(3)
       (8)(3)= 24
B.)24

C.) (4+3)-2
       (7)-2= 5
C.)5

D.) (4-2)+3
       (2)+3= 5
D.)5

Thus, B, is your answer.

B.(4×2)(3)=24 because 4×2=8, then times 8 to 3 which would give you 24.