Answer:
D,E are not functions
Step-by-step explanation:
A function is a relation in which every input has not more than one output.But the output of the inputs may be same.Here in D the input 1 has 4 different outputs as 1,2,3,4.So its not a function.Similarly in E 6 has 2 outputs as 2 and -1.For remaining sets the inputs has only one output.so they are functions.
Formula for volue of cylinder is area time height. Lets find area
A=

diameter=2r
8=2r
r=4
Now substitute r to

A=

Now we have formula
V=

- its the result, so B