With regard to stress, results from animal research indicated that a variety of stressors such as
a) maternal separation,
b) inescapable shock,
c) abrupt temperature change,
d) and loud noise

The answer is can weaken responses to antigens.

Explanation:

With regard to stress, results from animal research indicated that a variety of stressors such as  maternal separation,  inescapable shock,  abrupt temperature change,  and loud noise can weaken responses to antigens.

answer

the best answer is c

i would say b probably