The rate of the reaction  is influenced by the hyperconjugation effect of group R. If R sequentially is        the increasing order of speed of the above reaction is.

Consider the following carbocations :

(i) ${\mathrm{Cl}}_3{\mathrm{C}}^{+}$ (ii) ${\mathrm{Cl}}_2\stackrel{+}{\mathrm{C}}\mathrm{H}$ (iii) ${\mathrm{ClCH}}_2^{+}$ (iv) $\stackrel{+}{\mathrm{C}}{\mathrm{H}}_3$

The stability sequence follows the order:

The correct stability order for the following species is:

In the following carbocation $\mathrm{H}/{\mathrm{CH}}_3$ that is most likely to migrate to the positively charged carbon is