Answer
Option (a)
Work Step by Step
RECALL:
(1) The degree of a term is equal to the sum of the exponents of its variables.
(2) The degree of a polynomial is equal to the degree of the term with the highest degree.
The terms of the polynomial have the following degrees:
$2x^2y$: degree is 3
$7xy^3$: degree is 4
$5x^2y$: degree is 3
The highest degree among the three terms is $4$.
Thus, the degree of the polynomial is $4$.
Therefore, the answer is Option (a).