For a p-channel Si JFET, $$N_{a} = 3 \times 10^{16} cm^{-3}, N_{d}=10^{18} cm^{-3}$$. Channel thickness dimension is $$a = 0.33  \mu m$$. Find the approximate pinch-off voltage $$V_{p}. \left\{ n_{i}=10^{10} cm^{-3}, V_{r} = 26  mV, \ln (3) = 1.098 \right\}$$

A

2.5 V

B

1.7 V

C

4.2 V

D

3.6 V