The $IUPAC$ name of $CH_3-CH=CH-COOH$ is

Match the structures given in Column-$I$ with their $\text{IUPAC}$ names in Column-$II$.
| Column-$I$ (Structure) | Column-$II$ ($\text{IUPAC}$ Name) |
| :--- | :--- |
| $(A)$ Cyclohexanol | $(i)$ $2$-ethoxy-$1,1$-dimethylcyclohexane |
| $(B)$ $2$-methylcyclopentanol | (ii) $3$-methylphenol |
| $(C)$ $3$-methylphenol | (iii) Trihydroxybenzene |
| $(D)$ $1$-ethoxy-$2,2$-dimethylcyclohexane | (iv) $2$-methylcyclopentanol |
| $(E)$ Benzene-$1,2,4$-triol | $(v)$ Cyclohexanol |
| | (vi) Benzene-$1,2,4$-triol |

Which is the correct $IUPAC$ name of the following compound?
$CH_3-CH(CH_3)-CH(CH_2CH_3)-CH(CH_3)-CH_3$

Provide the $IUPAC$ name for the following compound:
$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,H\,\,\,\,\,{C_4}{H_9}} \\
{\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,|} \\
{CH_3CH_2 - C - C - CH_3} \\
{\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,|} \\
{\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,CH_3}
\end{array}$

The number of $C-C$ sigma bonds in the compound is:

The $IUPAC$ name of $CH_3-CH(CH_3)-CO-COOH$ is