Assertion (A): Free radical bromination of propane gives mainly 2-bromopropane, whereas chlorination gives a considerable amount of 1-chloropropane. Reason (R): Hydrogen abstraction by $\mathrm{Br}\cdot$ is endothermic, has a late transition state with high radical character, and therefore discriminates strongly between secondary and primary hydrogens.

1. ABoth A and R are true and R is the correct explanation of A
2. BBoth A and R are true but R is not the correct explanation of A
3. CA is true but R is false
4. DA is false but R is true