Half-wave recitifer diode (0.7v) problems
Tell your teacher that the question makes no sense because there's no way of determining the diode's PIV from the data given.

For instance, assume that in one case a diode with a PIV of 1000 volts was shown, and in another case a diode with a PIV of 100 volts was shown.

Ask your teacher how they'd determine the different  PIV's from the circuit and data given.