In the Section "Investigating Life: the Hidden Cost of Hygiene",what

In the section "Investigating Life: The Hidden Cost of Hygiene",what was the researchers' final conclusion?

A) Exposure to flatworms decreased interleukin levels,suppressing the immune system and leading to fewer allergies.
B) Exposure to flatworms increased interleukin levels,suppressing the immune system and leading to more allergies.
C) Exposure to flatworms decreased interleukin levels,suppressing the immune system and leading to more allergies.
D) Exposure to flatworms increased braking of interleukin levels,suppressing the immune system and leading to fewer allergies.
E) Exposure to flatworms decreased interleukin levels,but had no effect on the immune system or allergies.