The decreasing order of stability of the given carbocations is

Which of the following carbocations is expected to be most stable?

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

Arrange the following anions in decreasing order of their stability:
$CH_3^{\Theta}, NH_2^{\Theta}, OH^{\Theta}, Cl^{\Theta}$

Which of the following carbocations is most stable?

In the following species,the one which is likely to be the intermediate during benzoin condensation of benzaldehyde is