Judge the Following Sentence According to the Criteria Given Below

Judge the following sentence according to the criteria given below. Deltas are immune from the effects of sea-level rise because deltas are headlands that build into the sea by the deposition of river sediment.

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.