Explanation:

- The case of Mohammad Salimullah vs ________ in 2021 centered on the rights of refugees and deportation concerns.

- The Supreme Court observed that the 'Right not to be deported' is linked to Article 19, which guarantees certain freedoms, but is available only to Indian citizens.

- Option 1: State of Maharashtra - This does not fit the context of the national-level legal issue about deportation and rights which would involve the central government.

- Option 2: Union of India - This is the central government of India and is the correct answer because cases involving deportation and constitutional rights typically involve the Union of India.

- Option 3: State of Tripura - Similar to Maharashtra, this state-level body would not be a direct party in a nationwide constitutional issue about deportation.

- Option 4: Union Territory of Lakshadweep - Like the states, union territories are less likely to be involved in national judicial matters of this nature.