HELP ME PLEASE ASAP!!!

Which function has an inverse that is a function?

B(x) = x^2 +3
D(x)= -9
M(x)= -7x
P(x)= IxI


Which function has an inverse that is also a function?

-4,3 -2,7 -1,0 4,-3 11, -7

-4,6 -2,2 -1,6 4,2 11,2

-4,5 -2,9 -1,8 4,8 11,4

-4,4 -2,-1 -1,0 4,1 11,1