Answer:
a
Step-by-step explanation:
supplmentay angles are either of two angles whose sum is 180°
option b is two right angles (90 degree on both) add them together you get 180.
option c is 60 degrees and 120 degrees add them together to get 180 degrees.
option d is 155 degrees and add 25 degrees you get 180.
so the answer is a, because 30 degrees and add the other 30 degrees together you only get 60
