A single-phase full-wave AC phase controller feeds power to a resistive load of 100 Ω from a 220 V, 50 Hz supply. What will be the rms output voltage at delay angles $${\alpha _1} = {\alpha _2} = \alpha = \frac{\pi }{2}$$    of both transistors?

A. $$\frac{{220}}{{\sqrt 2 }}{\text{V}}$$

B. $$\sqrt {2 \times 220} {\text{ V}}$$

C. $$\sqrt 2 \times 110{\text{ V}}$$

D. $$\sqrt 2 \times 220{\text{ V}}$$

Answer: Option A