Assertion: Ambulacral system plays a major role in locomtion of echinoderm.
Reason: Hydraulic pressure of fluid and contraction of muscle of tube feet make possible movement of echinoderm.
A. IF both assertion and reason are true and the reason is the correct explanation of the assertion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. if assertion is true but the reason is false
D. if both are incorrect