Which amongst the following is not a Buddhist monastic
University?

The correct option is Takshashila.

To understand why Takshashila is the correct answer, let's look at the nature of each of the institutions mentioned:
1. Nalanda, Vikramshila, and Odantpuri were famous ancient seats of learning in India that were specifically established and developed as Buddhist monastic universities (Mahaviharas). They organized education around Buddhist texts, philosophy, and monastic rules, alongside other subjects.
2. Takshashila (also known as Taxila), located in modern-day Pakistan, was an ancient center of learning that predated the organized monastic university system of Buddhism. While it was a highly renowned hub of education where subjects like medicine, statecraft, philosophy, and military science were taught, it did not function as a structured Buddhist monastic university like Nalanda or Vikramshila. Instead, it was a collection of individual teachers and schools where students studied under specific gurus.

Therefore, Takshashila is not classified as a Buddhist monastic university, making it the correct choice.