The question asks to identify the scholar who authored a famous dissertation on Sanskrit grammar. Among the choices provided, Panini is widely recognized for his monumental work on the subject, the Aṣṭādhyāyī.
Panini, an ancient Indian linguist and scholar, is celebrated for composing the Aṣṭādhyāyī (meaning "Eight Chapters"). This work is considered the foundational text of Sanskrit grammar. It is a highly systematic and comprehensive treatise that precisely lays down the rules governing the structure, formation, and usage of Sanskrit language. Its analytical depth and rigorous methodology earn it the description of a 'dissertation' in the context of linguistic scholarship.
While the other individuals mentioned were influential figures, their primary contributions lie in different domains or represent different aspects of grammatical study:
| Scholar | Primary Area of Contribution | Connection to Sanskrit Grammar |
| Panini | Sanskrit Grammar | Author of the definitive foundational grammar, the Aṣṭādhyāyī. |
| Patanjali | Sanskrit Grammar (Commentary) | Wrote the Mahābhāṣya, a major commentary on Panini's rules, offering insights and defense of the grammar. |
| Sushruta | Ayurveda (Medicine) | Renowned physician known for the Sushruta Samhita, a text on surgery and medical practices. |
| Chanakya | Political Science, Economics | Authored the Arthashastra, a treatise on statecraft, economics, and military strategy. |
Considering the specific focus on a "famous dissertation on Sanskrit grammar," Panini's Aṣṭādhyāyī is the most fitting and historically significant work that matches this description.