An n-channel enhancement mode MOSFET is biased at $V_{GS}$ >$V_{TH}$ and $V_{DS}$ > $(V_{GS}-V_{TH})$, where $V_{GS}$ is the gate-to-source voltage, $V_{DS}$ is the drain-to-source voltage and $V_{TH}$ is the threshold voltage. Considering channel length modulation effect to be significant, the MOSFET behaves as a
- voltage source with zero output impedance
- voltage source with non-zero output impedance
- current source with finite output impedance
- current source with infinite output impedance