Answer:
D.
Step-by-step explanation:
cos is positive and sin is negative
=>
it must be in quadrant IV.
you remember, 1 = sin² + cos²
1 = sin² + (3/5)² = sin² + 9/25
25/25 = sin² + 9/25
16/25 = sin²
sin = 4/5 or -4/5
and as sin of this angle is < 0, our solution is -4/5
