Which one of the following is reverse-biased?

What is the current through an ideal $PN-$ junction diode shown in the figure below? (in $mA$)

The current-voltage relation of a diode is given by $I = \left( {{e^{\frac{{1000V}}{T}}} - 1} \right) \, mA$,where the applied voltage $V$ is in volts and the temperature $T$ is in Kelvin. If a student makes an error of $\pm 0.01 \, V$ while measuring the voltage to obtain a current of $5 \, mA$ at $300 \, K$,then the error in the value of the current in $mA$ is.....$mA$

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is......$A$

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: $A$ diode under reverse-biased condition provides very small current which is nearly independent of voltage until a critical limit at which the current increases drastically.
Reason $R$: Below the critical voltage limit, only majority charge carriers flow which increases drastically above critical voltage.

Avalanche breakdown is due to