Concept:A reverse-biased p-n junction has a wider depletion layer because the applied voltage pulls charge carriers away from the junction.
Explanation:In a p-n junction, the depletion layer is the region near the junction that is depleted of free charge carriers.
When reverse bias is applied, the p-side is connected to the negative terminal and the n-side is connected to the positive terminal.
This connection attracts majority carriers away from the junction: holes in the p-region move toward the negative terminal, and electrons in the n-region move toward the positive terminal.
As a result, more ions are left uncovered at the junction, so the depletion layer becomes wider.
The increased width creates a stronger barrier that opposes further current flow.
Therefore, reverse bias does not decrease, keep constant, or halve the depletion width; it increases it.
Answer:A. increased