According to Article 75 of the Constitution:
The Prime Minister must be a member of either House of Parliament — Lok Sabha or Rajya Sabha.
Even if not a member at the time of appointment, he/she must get elected to either House within 6 months.
Option Analysis:
- Option (A) and (B): Each is partially correct.
- Option (C): Correct and complete.
- Option (D): Being from a political party is not a constitutional requirement.