Which factors have psychologists identified as relating to the timing and intensity of stimuli that serve to strengthen conditioned responses?
a. Frequency of pairings, timing, and intensity of the conditioned stimulus
b. Frequency of pairings, timing, and intensity of the unconditioned stimulus
c. Frequency of pairings, timing, and intensity of the neutral stimulus
d. Frequency of pairings, timing, and intensity of the unconditioned response
