The "Hygiene Hypothesis" Suggests That Asthma Is the Result of Minimal

The "hygiene hypothesis" suggests that asthma is the result of minimal childhood exposure to chemicals that cause asthma attacks.According to this hypothesis,exposure to allergens in childhood strengthens the immune system's response to these relatively harmless molecules,making asthma cases uncommon.
-According to the "hygiene hypothesis," to reduce the chances of developing asthma,people raising children in

A) developing countries should keep their children away from farm animals.
B) developing countries should try to raise their children in cities.
C) cities in developed countries might want to have a pet dog or cat.
D) rural portions of developed countries should not have dogs or cats.