Assertion: Two possible carbon skeletons with four carbon atoms are:
Reason: Such compounds with more than 4 carbon atoms exhibit structural isomerism.
a) Both A and R are true, and R is correct explanation of the assertion.
b) Both A and R are true, but R is not the correct explanation of the assertion.
c) A is true, but R is false.
d) A is false, but R is true.