Which of the following is an example of elimination reaction?

Alkyl halides in presence of alcoholic base [alc. KOH] undergo elimination reaction. [i,e., de hydrohalogenation reaction].

Alcohols in presence of acid catalyst undergo elimination reactions. [i.e., de hydration reaction]

Note: → Alkanes [methane] undergo mainly free radical substitution reaction e.g: chlorination of methane

→ Benzene [Aromatic hydrocarbaons] mainly undergo electrophilic substitution reaction e.g: Nitration of benzene

→ Alkenes mainly under go electrophilic addition reactions. e.g: Hydration [hydroxylation] of alkene