Which equation is an identity?
A: 7-(9x+3)=-9x-4
B: 6m-5=7m+5-m
C: 10p+6-p=12p-3(p-2)
D3y+2=3y-2
A: 7-(9x+3)=-9x-4
B: 6m-5=7m+5-m
C: 10p+6-p=12p-3(p-2)
D3y+2=3y-2