Answer:
The value of x can be any integer greater than or equal to 0, and y will be an integer greater than or equal to 0.
Explanation:
Cost of 1 notebook = $3
x represents the number of notebooks
Since the number of notebooks cannot be negative .
So, x can be 0 or positive integer.
y represents the total cost of the notebooks .
Since Cost of 1 notebook is $3
So, Cost of notebooks will be in the multiples of 3.
So, y can be 0 or positive integer.
Thus Option D is correct.
The value of x can be any integer greater than or equal to 0, and y will be an integer greater than or equal to 0.