Explain that `(A)` readily forms an alkene with `I^(c-)` but `(B)` does not.

Explanation

In both `(A)` and `(B)`, two `Br` are in trans position. But in `(A)`, two `Br` are in trans`-` diaxial position and capable of `E2` elimination`:` while in `(B)`, both `Br` with are in trans `-` diequatorial position and are incapable of being eliminated.
(Remember that equatorial form is more stable than axial and, hence, equatorial form is less reactive than axial form.)