To answer this question, you need to have knowledge of the books written by Patanjali on Sanskrit grammar. Let's go through each option to understand why it is correct or incorrect:
Option A) Laghu Siddhant Kaumudi - This option is incorrect because Laghu Siddhant Kaumudi is a book on Sanskrit grammar written by Varadaraja.
Option B) Abhigyan Shakuntalam - This option is incorrect because Abhigyan Shakuntalam is a famous Sanskrit play written by Kalidasa.
Option C) Sutra-Ganga - This option is incorrect because Sutra-Ganga is not a book written by Patanjali on Sanskrit grammar.
Option D) Mahabhasya - This option is correct because Mahabhasya is a famous book on Sanskrit grammar written by Patanjali.
The correct answer is D) Mahabhasya. This option is correct because Mahabhasya is the book written by Patanjali on Sanskrit grammar.