Research indicates that using electronic devices before bed may make it difficult for people to fall asleep. the light appears to interfere with the bodys ability to create this hormones, which is responsible for sleep and wake cycles.

Dang it i was gonna answer but yeah its c

Your answer is c- spermicides!

Conjunctival membrane;

Of that are from eating black  foods or iron supplements. the most common condition causing  it is a bleeding ulcer.  black poop caused by blood indicate a problem in the upper digestive tract.     along with pain, vomiting, or diarrhea is cause to see a doctor right go see a doctor