The correct answer is the Supreme court of India.

• According to Article 71, the Supreme Court will investigate and settle all doubts and disputes arising out of the election of the President or Vice President, and its decision will be final.

• If there is any dispute, an election petition is filed with the Supreme Court of India which is the only authority to try an election petition regarding the President’s election.
• A petition regarding the dispute in the election can be filed by any of the presidential candidates.
• A petition can be filed by any 20 or more electors as joint petitioners.

• The Supreme Court of India is the highest judicial court under the Constitution of India.
• Article No 124 provides for the establishment and constitution of the Supreme Court.
• It is Established as the Supreme court of India on 28th January 1950 and its Headquarters in New Delhi.
• Also known as the 'guardian of our Constitution"
• The chief justice of India is the head of the Supreme Court of India.
• The 48th chief justice of India is Nuthalapati Venkata Ramana. 
• After the appointment of the new four justices on 18 September 2019, the strength of the Supreme court increases from 30 to 34.
• Newly appointed judges Krishna Murari, SR Bhat, V Ramasubramanian, and Hrishikesh Roy.
• The Parliament of India has the power to increase or decrease the number of judges in the Supreme court.