Explanation:

- Option 1: President

- The President does play a role in certain parliamentary procedures, but not directly in disqualification under the Tenth Schedule.

- Option 2: Speaker

- The Speaker of the Lok Sabha decides on disqualification matters related to the Tenth Schedule, which addresses disqualification on grounds of defection.

- The decision is based on the anti-defection law.

- Option 3: Prime Minister

- The Prime Minister does not have the authority to decide on disqualification matters under the Tenth Schedule.

- Option 4: Vice President

- The Vice President does not decide on these issues for the Lok Sabha. The Vice President is relevant to the Rajya Sabha as its Chairman.