What is the most suitable reagent for the conversion mentioned below?

\(\mathrm{CH_{3} — CH = CH — CH_{2} — \overset{\Large{O} \\~ ||}{C}—CH_{3} \rightarrow} \)
    
\(\mathrm{CH_{3} — CH = CH — CH_{2} — \overset{\Large{O} \\~ ||}{C}—OH}\)

1.  Tollens' reagent 

2.  Benzoyl peroxide

3.  \(\mathrm I_{2}\) and NaOH solution

4.  Sn and NaOH solution