To determine the number of enclaves in the border region between India and Bangladesh, let's consider the provided options:
1. 100
2. Less than 10
3. None of these
4. 25
5. More than 250
Based on historical and geographical information:
- The border region between India and Bangladesh had numerous enclaves, primarily due to historical treaties and agreements.
- Before the Land Boundary Agreement between the two countries, the number of enclaves was quite significant.
Taking all these into account, the correct answer is "more than 250."
So, the number of enclaves in the border region between India and Bangladesh is: more than 250.