The expression given in the question can be simplified by getting them out of the brackets and then adding and subtracting the like terms. This will yeild the desired result.
(-1+6i)+(-4+2i) = - 1 + 6i - 4 + 2i
= -5 + 8i
From the above deduction, it can be easily concluded that the correct option among all the options that are given in the question is the third option or option "c".