I have no idea.... please help. And explanation would be me most helpful thing at this point

Answer:
c) sin 126°
Step-by-step explanation:
cos(-576°)= -0.80901699437
cos 216°= -0.80901699437
-cos(-36)= -0.80901699437
sin 126°= 0.80901699437
-sin 54°= -0.80901699437
cos 144°= -0.80901699437