Which pair of groups exhibits the $(-I)$ effect?

The hyperconjugative stabilities of tert-butyl cation and $2-$butene,respectively,are due to

Identify the correct statements from the following :
a) Change in hybridisation affects the electronegativity of carbon
b) The $p$ orbitals in ethene are mutually parallel
c) The number of $\sigma$ bonds in propyne is $6$
d) Electromeric effect is a permanent 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:

Which of the following can show hyperconjugation?

Write the correct order of acidic strength for the following:
$(I) \ CH_3 - NO_2$
$(II) \ NO_2 - CH_2 - NO_2$
$(III) \ CH_3 - CH_2 - NO_2$
$(IV) \ (NO_2)_3CH$