Which among the given acids has the lowest $pKa$ value?

Which among the following pairs of electronic effect and its example is $NOT$ correct?

Negative inductive effect ($-I$ effect) is shown by:

Which group from the following is responsible for the $(-R)$ effect?

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:

In which of the following does the hyperconjugation effect operate?