The geometry of the reaction intermediate in an $S_N1$ reaction is:

The increasing order of basicity for the following intermediates is (from weak to strong):
$(i)$ $(CH_3)_3C^{-}$
$(ii)$ $H_2C=CH-CH_2^{-}$
$(iii)$ $HC \equiv C^{-}$
$(iv)$ $CH_3^{-}$
$(v)$ $CN^{-}$

The hybridization of the positively charged carbon and the negatively charged carbon in the following structures are respectively:

The most stable carbocation among the following is:

Arrange the following free radicals in order of decreasing stability:
$(A)$ Cyclohexyl-CH2-CH2•
$(B)$ Cyclohexyl-$CH$•-CH3
$(C)$ Cyclohexyl=$CH$-CH2•
(Note: The dot represents the radical center.)

Which one among the following carbocations is the most stable?