Step 1: Understanding the Concept:
The question asks to identify the Indian sage who systematized the "eight-fold path of yoga" (Ashtanga Yoga).
Step 2: Detailed Explanation:
(B) Patanjali: The sage Patanjali is credited with compiling the Yoga Sutras, a foundational text of yoga philosophy. In this work, he outlines the Ashtanga Yoga, or the eight-limbed path, as a systematic method to attain the final goal of God-realization or liberation (Moksha). The eight limbs are Yama (abstinences), Niyama (observances), Asana (postures), Pranayama (breath control), Pratyahara (withdrawal of senses), Dharana (concentration), Dhyana (meditation), and Samadhi (absorption).
(A) Gautam Buddha: Gautam Buddha also taught an "Eightfold Path" (Āryāṣṭāṅgamārga), but it is a central concept in Buddhism for achieving Nirvana and is distinct from the yogic path of Patanjali. The Buddhist path consists of Right Understanding, Right Thought, Right Speech, Right Action, Right Livelihood, Right Effort, Right Mindfulness, and Right Concentration.
(C) Socrates: Socrates was an ancient Greek philosopher and is not associated with the philosophy of yoga.
Step 3: Final Answer:
The eight-fold path of yoga was systematically presented by the sage Patanjali in his Yoga Sutras. Therefore, Patanjali is the correct answer.