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

Which of the following carbocations is the least stable?

The correct stability order for the following species is:
$(I)$ $o-CN-C_6H_4-CH_2^-$
$(II)$ $m-CN-C_6H_4-CH_2^-$
$(III)$ $p-CN-C_6H_4-CH_2^-$
$(IV)$ $C_6H_5-CH_2^-$
(Note: The image shows the structures of these carbanions.)

Due to the presence of an unpaired electron,free radicals are .........

In a carbonium ion,the carbon atom bearing the positive charge is in the:

$(C_6H_5COO)_2$ $\xrightarrow{hv} 2[X] + 2CO_2$ $\xrightarrow{} 2C_6H_5^\bullet + 2CO_2$
Consider the above reaction and identify the intermediate '$X$'.