Clemmensen reduction is a method to reduce the carbonyl group ($>C=O$) of aldehydes and ketones to a methylene group ($-CH_2-$) to form hydrocarbons. The reagent used for this reaction is Zinc Amalgam (Zn-Hg) and concentrated Hydrochloric acid (HCl).

Comparison of other options:

• LiAlH4: Reduces ketones to secondary alcohols.
• H2/Pt: Catalytic hydrogenation reduces ketones to secondary alcohols.
• Glycol with KOH: Used in Wolff-Kishner reduction (along with hydrazine) to achieve the same transformation ($>C=O$ to $-CH_2-$) but under basic conditions.