The 13th-century musical treatise 'Sangeet Ratnakar' was composed by:

"Sangeet Ratnakar" (Sangita Ratnakara) was written in the 13th century by Sharngadeva (Sarngadeva), a musician and scholar at the court of the Yadava king Singhana (Simhana) of Devagiri (present-day Daulatabad, Maharashtra). It is one of the most important texts on Indian music and is respected by both the Hindustani and Carnatic traditions as an authoritative source.

The book is written in Sanskrit and has seven chapters (adhyayas), covering:

• Swara (notes) and shruti (microtones).
• Raga (melodic frameworks), of which it describes 264.
• Prakirnaka (miscellaneous topics, including the qualities of singers).
• Prabandha (compositions).
• Tala (rhythm).
• Vadya (musical instruments).
• Nartana (dance).

Because it was written just before the period when Persian and Central Asian influences grew in North India, it is seen as a summary of Indian music before Hindustani and Carnatic music developed separately. Many later scholars wrote commentaries on it.

Other important texts on Indian music:

• "Natyashastra" by Bharata Muni (around 2nd century BCE to 2nd century CE), the oldest surviving text on drama, dance and music.
• "Brihaddeshi" by Matanga Muni (around 9th century), which first used the word "raga" in a technical sense.
• "Chaturdandi Prakashika" by Venkatamakhin (17th century), which set out the 72 melakarta ragas.
• "Swaramela Kalanidhi" by Ramamatya (16th century).

Why not the other options?

• ✗Bharata Muni wrote the Natyashastra.
• ✗Matanga Muni wrote the Brihaddeshi.
• ✗Venkatamakhin wrote the Chaturdandi Prakashika.