Find the correct stability order for the following carbocations:

Which of the following bridgehead carbocations is the most stable?

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:

Which of the following species $(A)$,$(B)$,$(C)$,and $(D)$ contain an $sp^2$ hybridized carbon atom? $(A) CH_3^+$,$(B) CH_3^-$,$(C) \dot{C}H_3$,$(D) :CH_2$

Which of the following carbocations is most stable?
$A) (CH_3)_2CH-CH^+-CH_3$
$B) (CH_3)_2C^+-CH_2CH_3$

Which of the following has an unstable enol form?