A square matrix like the one shown can be described as a singular matrix if its determinant is equal to zero.
The determinant can be calculated as the difference between the product of 5 and 6, and the product of 3 and x.
Determinant = (5 * 6) - (3 * x)
Determinant = 30 - 3x
Remember that one condition is for the determinant to be equal to zero, hence
30 - 3x = 0
30 = 3x
Divide both sides by 3
10 = x
The correct answer is option C