Answer:
c
Explanation:
How to remember which is which? Well, alphabetically they are:
Complementary add to 90°
Supplementary add to 180°
You can also think:
"C" of Complementary is for "Corner" right angle(a Right Angle), and
"S" of Supplementary is for "Straight" (180° is a straight line)
Or you can think:
when you are right you get a compliment (sounds like complement)
"supplement" (like a vitamin supplement) is something extra, so is bigger