To answer this question, you must put like-terms together,
since you can't subtract 5 with -4i or add 3i to 5
Right now the question is asking (5 - 4i) + (3 + 2i)
So you must use commutative property to get (5 + 3) + (2i - 4i)
So then your answer is...
8 - 2i, the third one