To remember the key terms used to describe pavlov's conditioning a dog to salivate to a bell, joshua vividly imagined that he was an experimental subject in pavlov's laboratory and that dr. pavlov was conditioning him to salivate. joshua was using to encode the information into long-term memory.

I believe Joshua was using: visual imagery
visual imagery is a memorization technique that is done by associating certain mental images with the new information.
By doing this, joshua would utilize both his right and left brain hemisphere and make it easier for him to recall the memory by simply picturing the mental images.

Ithink the answer you are looking for is (b).