Judge the following sentence according to the criteria given below: During low-oxygen conditions, ...

Judge the following sentence according to the criteria given below: During low-oxygen conditions, such as decomposing algal blooms or pollution events, most marine animals with gills can survive BECAUSE they can simply breathe air at the surface.
 
  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.