Identify the values of x and y that would make the following expression represent a real number.

(4 + 5i) (x + yi)

A. x = 4, y = 5

B. x = - 4, y = 0

C. x = 4, y = - 5

D. x = 0, y = 5

I think the correct answer from the choices listed above is option C. The values of x and y that would make the expression to represent a real number would be that x = 4, y = - 5. Substituting and simplifying,

(4 + 5i) (4 - 5i)

16 - 20i + 20i - 25i²

16 - 25 (-1)

16 + 25

41