"Her mom can make Kung Pao Chicken."
会 is often used for skill or know-how, and 能 for bare capability. There's some overlap, however. And 能 along with 可以 can be used for possibility.
I suppose it's difficult to say exactly what the so-called right choice is here without making assumptions as to what the underlying meaning of "can" is.
To my knowledge, "丁" is part of the standard name for this dish. In any event, the only other instances of 宫保鸡 that I've been able to find in Duolingo exercises are the following, which have the "丁":