Assertion (A): Saturated hydrocarbons are chemically less reactive. Reason (R): All the valencies of carbon atoms are satisfied by single covalent bonds.

a) Both A and R are true, and R is the correct explanation of A.

b) Both A and R are true, but R is not the correct explanation of A.

c) A is true, but R is false.

d) Both A and R are false.