Taking into account the stability of various carbocations and the rules governing mechanisms of carbocation rearrangements,which reaction is most likely to occur during the given reaction?

Given below are two statements:
Statement $I$: $(CH_3)_3C^{+}$ is more stable than $CH_3^{+}$ as nine hyperconjugation interactions are possible in $(CH_3)_3C^{+}$.
Statement $II$: $CH_3^{+}$ is less stable than $(CH_3)_3C^{+}$ as only three hyperconjugation interactions are possible in $CH_3^{+}$.
In the light of the above statements,choose the correct answer from the options given below.

What is the correct order of stability for $1^\circ, 2^\circ, 3^\circ$ carbocations and benzyl carbocation?

$A$ carbanion acts as a:

The correct order of stability of the carbocations given below is:

Which of the following is the electrophile involved in the given reaction?