State Whether the Function Is a Polynomial Function or Not $f ( x ) = 5 x + 7 x ^ { 3 }$

Multiple Choice

State whether the function is a polynomial function or not. If it is, give its degree. If it is not, tell why not.
- $f ( x ) = 5 x + 7 x ^ { 3 }$

A) Yes; degree 7
B) Yes; degree 1
C) Yes; degree 3
D) Yes; degree 5