When You Have P-Type Silicon and N-Type Silicon Joined Together

When you have p-type silicon and n-type silicon joined together, why don't electrons dislodged by light in the n-type cross the junction barrier and enter the p-type?

A) The junction barrier is unidirectional. Electrons can only move from the p-type to the n-type silicon through the junction.
B) The photoelectric effect causes a charge buildup which prevents the flow of electrons in either direction across the junction barrier.
C) The boron in p-type silicon's crystal lattice must maintain its "electron holes" as bonding sites. This prevents the electrons dislodged by light in n-type silicon from crossing the junction barrier.
D) The arsenic in n-type silicon has an extra valence electron whereas the boron in p-type silicon is missing one. This difference inhibits the electrons dislodged by light in the n-type from crossing the junction barrier.