An amplifier without feedback has a voltage gain of 50, input resistance 1 kΩ and output resistance of 2.5 kΩ. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback factor of 0.2 would be:

A

$$\frac{1}{11}$$ kΩ

B

$$\frac{1}{5}$$kΩ

C

5 kΩ

D

11 kΩ