Meg develops a hypodermic needle phobia following a painful, bruising injection. However, Meg develops no fear of other sharp objects such as sewing needles, scissors, or knives. Meg's example demonstrates:

Stimulus discrimination

Explanation:

Stimulus discrimination is a concept in behaviorist learning theory, which refers to the tendency of an organism or an individual to respond differently to a different stimulus, rather than responding the same way to other similar stimulus. As seen in the case of Meg, she is able to discriminate between the painful bruising injection and other similar sharp objects, as she doesn’t respond to other object the same way she responds to the injection.

i agree d is most definitely correct!