Match the following.

List-I	List-II
a. Sucking and eye blinking	1. Classical conditioning
b. Less than 2.5 kg, of birth weight	2. Loneliness
c. Empty nest	3. Operant conditioning
d. Pairing of stimuli	4. Permanent reflex
	5. Small for date
	6. Broken homes

A. a-5, b-2, c-6, d-3

B. a-6, b-5, c-2, d-3

C. a-2, b-4, c-6, d-1

D. a-4, b-5, c-2, d-1

Answer: Option D