Part A
f(0)
that means the value of f(x) for x=0
looking at the table
For x=0 ----> f(x)=4
therefore
f(0)=4
Part B
f(x)=0
looking at the table
f(x)=0 when the value of x=1
therefore
f(1)=0
Part C
f^-1(0)
For f(x)=0 -----> the value of x=1
therefore
f^-1(0)=1
Part D
f^-1(x)=0
looking at the table
For x=0 -----> f(x)=4
therefore
f^-1(4)=0