In the following reaction,which type of reaction intermediate is likely to be involved?

Using curved-arrow notation,show the formation of reactive intermediates when the following covalent bonds undergo heterolytic cleavage:
$(a)$ $CH_{3}-SCH_{3}$
$(b)$ $CH_{3}-CN$
$(c)$ $CH_{3}-Cu$

Which of the following intermediates is not expected to be formed in the following reaction?

What is the shape of the methyl carbocation,$\overset{\oplus}{C}H_3$?

The most stable carbocation among the following is:

Which of the following is the most stable carbanion?