Answer:
A. (0, 5)
Explanation:
Physically speaking, the volume of the box and the side of the square cutout are positive value. So that the following inequations must be satisfied:
(1)
(2)
(3)
From (1), (2), (3) we find that:
(1):

(2):



(3):



We see that equation above is the multiplication of a first grade monomial and two first grade binomials, which means that:


In other words, the reasonable domain for this situation is A.