What is meant by 'Usurpation' in the context of Vijayanagara?

It refers to the forceful seizure of the throne by military leaders (like the Saluvas and Tuluvas) when the ruling dynasty became too weak to defend the state.

Vijayanagara Succession: Saluva to Tuluva Dynasty

Q: Consider the following Statements: 1. Narasimha Saluva ended the Sangama dynasty and seized the throne for himself and started the Saluva dynasty 2. Vira Narasimha deposed the last Saluva ruler and seized the throne for himself 3. Vira Narasimha was succeeded by his younger brother, Krishnadeva Raya 4. Krishnadeva Raya was succeeded by his half-brother, Achyuta Raya Which of the statements given above are correct?

The Vijayanagara Empire saw transitions from the Sangama to Saluva and Tuluva dynasties through military usurpation. Krishnadeva Raya, the most famous ruler, succeeded his brother Vira Narasimha and was followed by his half-brother Achyuta Raya.

ID: MED_VIJ_2004_21 Ref: K.A. Nilakanta Sastri, A History of South India

Consider the following Statements:
1. Narasimha Saluva ended the Sangama dynasty and seized the throne for himself and started the Saluva dynasty
2. Vira Narasimha deposed the last Saluva ruler and seized the throne for himself
3. Vira Narasimha was succeeded by his younger brother, Krishnadeva Raya
4. Krishnadeva Raya was succeeded by his half-brother, Achyuta Raya

Which of the statements given above are correct?