PLS HELP I RLY NEED IT

If the sin 30º = 1/2
then which statement is true? (6 points)

a. cos 150° = 0, because the cosine and sine are supplements

b. cos 60° = 0, because the cosine and sine are complements

c. cos 150° = 1, because the cosine and sine are supplements

d. cos 60° = 1/2, because the cosine and sine are complements