The correct stability order for the following species is:

What is the order of stability of the following carbocations?
$(X). CH_3 - \overset{\oplus}{C}H - CH_3$
$(Y). CH_3 - \overset{\oplus}{C}H - OCH_3$
$(Z). CH_3 - \overset{\oplus}{C}H - COCH_3$

Which of the following is more stable than the remaining three?

Among the following carbocations:
$(I)$ $Ph_{2}\stackrel{+}{C} CH_{2} Me$
$(II)$ $Ph CH_{2} CH_{2} \stackrel{+}{C} HPh$
$(III)$ $Ph_{2} CH \stackrel{+}{C} HMe$
$(IV)$ $Ph_{2} C(Me) \stackrel{+}{C} H_{2}$
The order of stability is:

In the following carbocation,the $H$ or $CH_3$ group that is most likely to migrate to the positively charged carbon is:

For the following carbocations, the correct order of stability is:
$I: ^+CH_2-COCH_3$
$II: ^+CH_2-OCH_3$
$III: ^+CH_2-CH_3$