Assertion: Red algae contribute in producing coral reefs.
Reason: Some red algae secrete and deposit calcium carbonate over their walls.
Both the Assertion and the Reason are true and the Reason is a correct explanation of the Assertion.
Both the Assertion and the Reason are true but the Reason is not a correct explanation of Assertion.
Assertion is true but the Reason is false.
Assertion is false but the Reason is true.