It’s C.
There are a lot of ways to do midpoint, but I like to separate it into x and y and then combine the two. If you find the average of the two x coordinates ((A(x) + B(x) / 2), you get the midpoint of the x’s.
4 + (-6) = -2
-2 / 2 = -1
-1 is the x, now do the same for the y.
-6 + (-4) = -10
-10 / 2 = -5
-5 is the y.
All you have to do now is format it. It’s always (x, y) so the answer is (-1, -5) or C.