13. Person A participated in five tests, each with a full score of 100 points. A's score in each test is a natural number between 0 and 100, inclusive of 100. It is known that A scored the same in the first four tests and scored higher in the last test. If A's average score over the five tests is 82 points, then the number of possible scores for the last test is ( ).
(A) 4
(B) 5
(C) 9
(D) 10
(E) 18
13. A.

Let the scores of the first four tests be $x$, and the score of the last test be $y$.
Then $4x + y = 410$. Clearly, $y$ is even.
Given $x < 82$.
If $y = 100$, then $x \notin \mathbf{Z}_{+}$. Therefore, the maximum value of $y$ is 98. Thus, the minimum value of $x$ is 78.

Upon verification, $x$ can be $78, 79, 80, 81$, all of which satisfy the conditions, resulting in 4 possible scenarios.