The expounder of yoga philosophy is:

Detailed Solution:

The correct answer is “Patanjali”.

Patanjali is considered the "Father of Yoga" and is best known for his seminal work, the Yoga Sutras, which is a foundational text of yoga philosophy.

The Yoga Sutras, compiled around 2nd century BCE, provide a systematic exposition of yoga's principles and practices, encompassing physical postures, breathing techniques, meditation, and ethical guidelines.