Which of the following is the most stable free radical?

Arrange the following carbocations in the increasing order of stability with respect to their labels:

Label	Carbocation
$1$	$CH_3-CH^+-CH_3$
$2$	$CH_3^+$
$3$	$(CH_3)_3C^+$
$4$	$CH_3-CH_2^+$

Which of the following is the most stable carbocation?

Consider the following statements. Of these statements:
$(I) \ CH_3O-CH_2^+$ is more stable than $CH_3-CH_2^+$
$(II) \ Me_2CH^+$ is more stable than $CH_3-CH_2-CH_2^+$
$(III) \ CH_2=CH-CH_2^+$ is more stable than $CH_3-CH_2-CH_2^+$
$(IV) \ CH_2=CH^+$ is more stable than $CH_3-CH_2^+$

Which of the following intermediates has a complete octet around the carbon atom?

Given below are two statements:
Statement $I$: $(CH_3)_3C^{+}$ is more stable than $CH_3^{+}$ as nine hyperconjugation interactions are possible in $(CH_3)_3C^{+}$.
Statement $II$: $CH_3^{+}$ is less stable than $(CH_3)_3C^{+}$ as only three hyperconjugation interactions are possible in $CH_3^{+}$.
In the light of the above statements, choose the correct answer from the options given below.