Who among the following has worked in the field of mathematical astronomy ?

Ancient and medieval Indian scholars each specialised within distinct branches of mathematics — some concentrated on planetary positions, eclipse timing, and calendrical computation, the branch known as mathematical astronomy, while others worked mainly on algebra, arithmetic, or number theory.

Aryabhatta's 5th-century treatise, the Aryabhatiya, covers planetary motion, eclipse calculation, and the Earth's rotation, placing his documented work within mathematical astronomy. Bhaskara I, in the 7th century, extended this same tradition through his commentary on the Aryabhatiya and his own treatise, the Mahabhaskariya, both devoted to astronomical computation. Since both scholars' major works fall within mathematical astronomy, the combination "Aryabhatta and Bhaskara I" is the complete answer — matching the official CTET August 2023 Paper I answer key.

• Srinivasa Ramanujan's documented contributions are in number theory, infinite series, and modular functions (early 20th century) — a different branch of mathematics from celestial computation.

• Mahavira's treatise, the Ganita Sara Sangraha (9th century CE), is devoted to arithmetic and algebraic methods, not celestial computation.

• A single scholar's name by itself cannot capture a combination answer once the question offers a joint option covering more than one name — each name must be checked against the stem's criterion before selecting.