Explanation:

- Hasrat Bibi vs. Ghulam Jaffar is a legal case dealing with the concept of acknowledgment in Muslim Law, especially regarding legitimacy or paternity.

- Option 1: Nikah – This relates to Muslim marriage. The case is not about marriage validation.

- Option 2: Dower – Dower (mehr) is the mandatory payment by husband to wife in marriage. The case is not about this.

- Option 3: Marz-ul-Maut – Marz-ul-maut refers to death-bed illness, affecting the validity of gifts or transfers. The case is not about this.

- Option 4: Acknowledgment – Correct! The case is primarily about the acknowledgment of legitimacy in personal law.