Which is the most stable carbocation?

Among the given compounds $I, II, III$,the correct order of bond dissociation energy of the $C-H$ bond marked with $*$ is:

Which of the following is most likely to undergo a favorable hydride shift?

Arrange the following in decreasing order of stability.
$(i)$ $CH_3^{\bullet}$,$(CH_3)_3C^{\bullet}$,$(CH_3)_2CH^{\bullet}$ and $CH_3CH_2^{\bullet}$
$(ii)$ $CH_3CH_2^{+}$,$(CH_3)_3C^{+}$,$(CH_3)_2CH^{+}$ and $CH_3^{+}$

Write in ascending order of stability of $1^{\circ}$,$2^{\circ}$ and $3^{\circ}$ carbocations and free radicals.

Provide four formulas of carbocations.