The correct answer is: a) Odia.
Odia is the official language of Odisha, India. It is spoken by about 35 million people, making it the 10th most spoken language in India. Odia is a member of the Indo-Aryan language family, and is closely related to Bengali and Assamese.
Hindi is the official language of India, and is spoken by about 400 million people. It is a member of the Indo-Aryan language family, and is closely related to Urdu. Hindi is the most widely spoken language in India, and is used in government, education, and the media.
Santali is a tribal language spoken by about 7 million people in India and Bangladesh. It is a member of the Munda language family, and is closely related to Ho. Santali is the most widely spoken tribal language in India, and is used in education and the media.
Ho is a tribal language spoken by about 1 million people in India and Bangladesh. It is a member of the Munda language family, and is closely related to Santali. Ho is used in education and the media.
In conclusion, the correct answer to the question “Which of these languages is spoken by the largest number of people in Odisha?” is a) Odia.