The correctly matched pairs of the following are given by the sets $:$
$(A)$ Neopentane $-$ position isomer of isopentane
$(B)$ Isopentane $-$ three primary carbon atoms
$(C)$ Isobutylene $-$ no secondary carbon
$(D)$ Isobutane $-$ two primary carbons

Which is correctly matched?

Enol content is highest in

The enolic form of acetone contains:

Among the compounds
$(i)$ $HC \equiv C-COOH$
$(ii)$ $CH_2=CH-COOH$
$(iii)$ $CH_3-CH_2-COOH$ and
$(iv)$ $CH_3-CH_2-OH$
The correct order of acid strength is

Given below are two statements:
Statement-$I$ : Compound $(X)$, shown below, dissolves in $NaHCO_3$ solution and has two chiral carbon atoms.
Statement-$II$ : Compound $(Y)$, shown below, has two carbons with $sp^3$ hybridization, one carbon with $sp^2$ and one carbon with $sp$ hybridization.
In the light of the above statements, choose the correct answer from the options given below: