Which of the following compounds gives the most stable carbocation upon dehydrogenation?

Arrange the following carbanions in the decreasing order of stability:
$I. \ p-Br-C_6H_4-CH_2^-$
$II. \ C_6H_5-CH_2^-$
$III. \ p-CH_3O-C_6H_4-CH_2^-$
$IV. \ p-CHO-C_6H_4-CH_2^-$
$V. \ p-CH_3-C_6H_4-CH_2^-$
Choose the correct answer from the options given below:

The most stable carbocation among the following is:

What is the order of stability of carbon free radicals among ${3^\circ}$,${2^\circ}$,${1^\circ}$,and $\mathop C\limits^\bullet {H_3}$?

Consider the following carbocations. What is the relative stability order of these carbocations?
$(1)$ $CH_3O-C_6H_4-CH_2^+$
$(2)$ $C_6H_5-CH_2^+$
$(3)$ $CH_3-C_6H_4-CH_2^+$

The correct stability order of the following carbocations is:
$I$. $H_2C^+-CH=CH-CH_3$
$II$. $H_2C^+-CH=CH-BMe_2$
$III$. $H_2C^+-CH=CH-NMe_2$
$IV$. $H_2C^+-CH=CH-OMe$