Which of the following is the correct decreasing order of stability of carbanions?
$(1) (CH_3)_3C^-$
$(2) (CH_3)_2CH^-$
$(3) CH_3CH_2^-$
$(4) C_6H_5CH_2^-$

Which one of the following species is most stable?

Rank the transition states that occur during the following reaction steps in order of increasing stability (least $\to$ most stable):
$1. CH_3-OH_2^+ \to CH_3^+ + H_2O$
$2. (CH_3)_3C-OH_2^+ \to (CH_3)_3C^+ + H_2O$
$3. (CH_3)_2CH-OH_2^+ \to (CH_3)_2CH^+ + H_2O$

The increasing order of stability of the following free radicals is:

Arrange the following carbanions in the decreasing order of stability:
$I. \ p-Br-C_6H_4-CH_2^-$
$II. \ C_6H_5-CH_2^-$
$III. \ p-CH_3O-C_6H_4-CH_2^-$
$IV. \ p-CHO-C_6H_4-CH_2^-$
$V. \ p-CH_3-C_6H_4-CH_2^-$
Choose the correct answer from the options given below:

Explain why $((CH_3)_3C)^+$ is more stable than $(CH_3CH_2)^+$ and $(CH_3)^+$ is the least stable carbocation.