Input reflection coefficient ‘S11’ of the 2-port network for 50 Ω system is:

A

$$\frac{1}{3} \angle{0^\circ}$$

B

$$\frac{1}{2} \angle{180^\circ}$$

C

$$\frac{1}{3} \angle{180^\circ}$$

D

$$\frac{1}{2} \angle{0^\circ}$$