A. The modulus is 5 sqrt2.
C. It lies in quadrant 2.
To determine the modulus, we use the formula:
|a + bi| = sqrt(a^2 + b^2)
So for 5 - 5i,
|5 - 5i| = sqrt(5^2 + (-5)^2) = sqrt(50) = 5 sqrt2
And since the real part is positive and the imaginary part is negative, the complex number lies in quadrant 2.