Arrange the following alkyl halides in order of increasing reactivity towards $SN^1$ reaction.

(A) $(CH_3)_3C-I$
(B) $(CH_3)_3C-F$
(C) $(CH_3)_3C-Br$
(D) $(CH_3)_3C-Cl$

Choose the correct answer from the options given below:

(B), (D), (C), (A)

The correct answer is Option (1) → (B), (D), (C), (A)

SN1 rate depends mainly on leaving group ability (I⁻ > Br⁻ > Cl⁻ > F⁻).
All compounds form the same tert-butyl carbocation, so only the halide matters.

Increasing reactivity:

$\text{(CH₃)₃C–F} < \text{(CH₃)₃C–Cl} < \text{(CH₃)₃C–Br} < \text{(CH₃)₃C–I}$

Correct option: (B), (D), (C), (A)