Why do firefighters use oxygen gas tank

You can drink laxative, or  do this exercise when you are sitting in the bathroom on the toilet. to relieve  constipation  fast or in about 1 minute, pinch your nose after your usual exhalation. start holding your breath. but do not mouth breath during this just hold your breath. 

Ithink the answer is d. the lower appellate and trial courts in the state.