C-08-Q221mediumsingle_mcqWith the same setup, ∠YNZ\angle YNZ∠YNZ equals—a90∘+12∠X90^{\circ} + \frac{1}{2}\angle X90∘+21∠Xb90∘−12∠X90^{\circ} - \frac{1}{2}\angle X90∘−21∠Xc∠X\angle X∠Xd12∠X\frac{1}{2}\angle X21∠X