Answer:
C. (-1)(15+15+15+15)
D. (-15)+(-15)+(-15)+(-15)
Step-by-step explanation:
The original expression: 4(-15)=-60
Let's try choice A: 15+15+15+15=60(not a negative number, so does not work)
Let's try choice B: 4+4+4+4=16(nowhere near -60)no
Let's try choice C: (-1)(15+15+15+15)=(-1)(60)=-60--yes
Let's try choice D: (-15)+(-15)+(-15)+(-15)=-60--yes
Only choices C and D work.