Let's think step by step! What will die without a supply of blood?
Options:
- (A) plants
- (B) organs
- (C) brain cells
- (D) athletes
- (E) humans
- (F) species
- (G) critical organs
- (H) mushrooms
The thinking starts now:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Brain cells die quickly if their oxygen supply is cut off. Here, the lungs supply the blood with oxygen. Brain cells die quickly if their blood supply is cut off. The final answer: (C).