Number one:
-4c - 6d + 9c + 2d
~Combine like terms
(-4c + 9c) + (-6d + 2d)
~Simplify
5c - 4d (Option A)
Number two:
2(-y + 9) + 8y
~Distribute
-2y + 18 + 8y
~Combine like terms
(-2y + 8y) + 18
~Simplify
6y + 18 (Option C)
Number three:
-3(-4y + 5) - 8y
~Distribute
12y - 15 - 8y
~Combine like terms
4y - 15 (Option C)
Number four:
6c - 8d + 3c + 4d
~Combine like terms
(6c + 3c) + (-8d + 4d)
~Simplify
9c - 4d (Option A)
Best of Luck!