For the n-channel enhancement MOSFET shown in figure, the threshold voltage Vth = 2 V. The drain current ID of the MOSFET is 4 mA when the drain resistance RD is 1 kΩ. If the value of RD is increased to 4 kΩ, drain current ID will become
1
2.8 mA
2
2.0 mA
3
1.4 mA
4
1.0 mA