Judge the following sentence according to the criteria given below: Most marine organisms are ...

Judge the following sentence according to the criteria given below: Most marine organisms are affected by the high pressure at depth BECAUSE they do not have large internal air pockets that can be compressed.
 
  A) The assertion and the reason are both correct, and the reason is valid.
  B) The assertion and the reason are both correct, but the reason is invalid.
  C) The assertion is correct, but the reason is incorrect.
  D) The assertion is incorrect, but the reason is correct.
  E) Both the assertion and the reason are incorrect.