Step 1:
\P-n junction diode:
\D. It has heavily doped p-type and n-type regions separated by an intrinsic region.
\Varactor diode:
\A. Its operation depends on the capacitance that exist at the p-n junction which is reverse biased.
\Tunnel diode:
\C. It has a negative resistance region where an increase in terminal voltage results in reduction in the diode current.
\Zener diode:
\B. It permits the current to flow in the forward bias direction but it will also flow in the reverse bias when the voltage is above the breakdown voltage.
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Vp = 14 V
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