Which of the following will give positive iodoform test?

The major product of the following reaction is

Cyclopentanol on reaction with $\mathrm{NaH}$ followed by ${\mathrm{CS}}_2$ and ${\mathrm{CH}}_3\mathrm{I}$ produces a/an

Identify $\mathrm{X}$ and $\mathrm{Y}$ in the following reactions

$\mathrm{R}-\mathrm{CH}=\mathrm{CH}-{\mathrm{CH}}_2\mathrm{OH}\stackrel{\mathrm{X}}{\to }\mathrm{R}-\mathrm{CH}=\mathrm{CH}-\mathrm{CHO}$
$\mathrm{R}-{\mathrm{CH}}_2\mathrm{OH}\stackrel{\mathrm{Y}}{⟶}\mathrm{R}-\mathrm{COOH}$

Which is the most suitable reagent for the following transformation?