Explanation:

- The correct option for the sentence of imprisonment for offering dowry through advertisement is Option 1: 6 months.

- Dowry is a social evil addressed by the Dowry Prohibition Act, 1961 in India, which seeks to eradicate the practice.

- Part of this act prohibits advertising or offering to give dowry, with strict penalties.

- The law prescribes a punishment that can extend to imprisonment for up to 6 months.

- Option 1: 6 months is the correct answer as per the legal provisions related to dowry advertisements.