Explanation:
Hello, So use the function p, to find the output


Since p(4)>p(5) and p(3), p(4) is the maximum.
Also p is written in vertex form which is

Since a is negative, we will have a maximum vertex.
The answer is
Oriya has reasoned the vertex is a maximum because p(4) is the highest points compared to points near it such as p(3) and p(5).