Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) : 1-iodobutane undergoes ${\text{S}}_{\text{N}}2$ reaction faster than 1-chlorobutane.Reason (R) : Iodine is a better leaving group because of its large size.In the light of the above statements, choose the correct answer from the options given below :

1. Assertion (A): In ${\text{S}}_{\text{N}}2$ reactions, the rate depends on the leaving group ability. Iodide (${\text{I}}^{-}$) is a much better leaving group than Chloride (${\text{Cl}}^{-}$). Thus, 1-iodobutane reacts faster. A is true.2. Reason (R): Iodine is a better leaving group due to its large size, which results in a weaker and more polarizable C-I bond compared to C-Cl. Its large size also allows it to stabilize the negative charge better. R is true.Since the leaving group ability (Reason) directly explains why the reaction is faster (Assertion), R is the correct explanation for A.