Which of the following carbocations will be most stable?

The decreasing order of hydride affinity for the following carbocations is:
$A: CH_2=CH-C^+(CH_3)_2$
$B: (C_6H_5)_3C^+$
$C: (CH_3)_3C^+$
$D: (Cyclopropyl)_3C^+$
Choose the correct answer from the options given below:

Arrange the following free radicals in order of decreasing stability:
$(A)$ Cyclohexyl-CH2-CH2•
$(B)$ Cyclohexyl-$CH$•-CH3
$(C)$ Cyclohexyl=$CH$-CH2•
(Note: The dot represents the radical center.)

Arrange the $(C-H)$ bonds $x, y$ and $z$ in decreasing order of their bond dissociation energies in homolysis.

Consider the following compound $(X)$:
$H-C \equiv C-CH_2-CH(CH_3)-CH_3$
The most stable and least stable carbon radicals,respectively,produced by homolytic cleavage of the corresponding $C-H$ bond are:

How many carbon-hydrogen bond orbitals are available for overlap with the vacant $p$-orbital in ethyl carbocation?