Which of the following was NOT a learning center of ancient India?

Correct option is C

Koushambi was an important ancient city but not a notable center of learning. Nalanda, Takshshila, and Vikramshila were renowned for education, philosophy, and cultural exchange. Explanation of options: (a) ✘ Nalanda was a premier ancient university. (b) ✘ Vikramshila was founded by the Pala kings as a learning center. (c) ✔ Koushambi was a political city, not an educational hub. (d) ✘ Takshshila was one of the earliest learning centers in India.