Arrange the following carbanions in decreasing order of stability $:$

Which of the following orders of rotation barrier about the $C=C$ bond,as indicated in the structures $(I)$,$(II)$,and $(III)$,is correct?

Explain why alkyl groups act as electron donors when attached to a $\pi$ system.

Which of the indicated $H$ in the following is most acidic?

What is the correct order of decreasing acidity for the following compounds?

Given below are two statements,one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : Order of acidic nature of the following compounds is $A > B > C$.
(Image shows: $A$ is $2$-chlorocyclohexanol,$B$ is $4$-fluorocyclohexanol,$C$ is $3$-methylcyclohexanol)
Reason $R$ : Fluoro is a stronger electron withdrawing group than Chloro group.
In the light of the above statements,choose the correct answer from the options given below: