Answer : 3. "जबड़ा "
Explanation :

The masseter muscle, which is one of the muscles used for chewing and is located in the jaw, is often considered one of the most powerful muscles in the human body in terms of its force and capability. However, the term "most powerful" can be interpreted in different ways, considering factors like strength, endurance, or speed. Different muscles might be considered the most powerful depending on the specific criteria used.