The Blocking Phenomenon Is Said to Occur When

Multiple Choice

The blocking phenomenon is said to occur when

A) a preexposed stimulus develops into a strong excitatory CS during training.
B) a conditioned inhibitor is easily converted into a strong excitatory CS during training.
C) nothing is learned about a novel stimulus despite compound training with an established excitatory CS.
D) pairing a novel stimulus with an established excitatory CS prevents learning anything about the compound.