Richard Is Studying Both French and Spanish

Richard is studying both French and Spanish. In the same week he learns that the French word for "mother" is mère and that the Spanish word for "mother" is madre. One day his French teacher asks Richard, "Who is married to your father?" and Richard erroneously answers, "Madre." Richard's memory error can best be explained in terms of:

A) decay
B) interference
C) source monitoring
D) failure to consolidate