Which of the two stereoisomers of 4-t-butylcyclohexyl iodide (¹²⁷I^-) will undergo ${\mathrm{S}}_{{\mathrm{N}}^2}$substitution with ¹²⁸I^- faster, and why ?

A will react faster because it will yield a more stable product, and the transition state for both reactions is of the same energy

A will react faster because the approach of ¹²⁸I^- can depart unhindered.

A will react faster because it is the more stable of the two isomers

B will react faster because it is less stable than A, and the transition state for both reactions is of the same energy