Hey there!
For this one, we need to use the distributive property which states that:
a(b+c) = ab + ac
If we look at A, it says:
28(1+7) which would get us 28(1) + 28(7) which does not equal 28+45
For B, we have:
7(4 + 5), which equals 7(4) + 7(5) = 28 + 35.
Therefore, B is your answer.
Hope this helps!