Consider two complex numbers `alphaa n dbeta` as `alpha=[(a+b i)//(a-b i)]^2+[(a-b i)//(a+b i)]^2`, where a ,b , in R and `beta=(z-1)//(z+1), w here |z|=1,` then find the correct statement: both `alphaa n dbeta` are purely real both `alphaa n dbeta` are purely imaginary `alpha` is purely real and`beta` is purely imaginary `beta` is purely real and `alpha` is purely imaginary