Identify the Expression as a Polynomial or Not a Polynomial $7 x ^ { 2 } y ^ { 3 } - 4 x ^ { 3 } y - 3 x$

Multiple Choice

Identify the expression as a polynomial or not a polynomial.
- $7 x ^ { 2 } y ^ { 3 } - 4 x ^ { 3 } y - 3 x$

A) Polynomial
B) Not a polynomial