Answer: Choice A. Distributive property
This is using the idea that if (a+b)(c+d+e), then it distributes to a(c+d+e)+b(c+d+e).
It might help to let y = c+d+e.
(a+b)(c+d+e) = (a+b)y
(a+b)(c+d+e) = y(a+b)
(a+b)(c+d+e) = y*a+y*b
(a+b)(c+d+e) = a*y + b*y
(a+b)(c+d+e) = a*(c+d+e) + b*(c+d+e)
