Which of the following carbocations is most likely to undergo a favorable 1,2 -hydride shift to form a more stable carbocation?

Step-by-step solution

To determine which carbocation is most likely to undergo a favorable 1,2 -hydride shift, we evaluate the possible rearrangements for each given structure. In option (A), the structure is the 3 -methylbutan- 2 -yl cation, which is a secondary ( 2^ ) carbocation. The adjacent carbon atom is tertiary and possesses one hydrogen atom. A 1,2 -hydride shift from this tertiary carbon to the positively charged carbon forms the 2 -methylbutan- 2 -yl cation. This new carbocation is tertiary ( 3^ ) and has 8 -hydrogens, making