Considering this as Class C network. 200.1.15.255. So, first 3 Octet is Net ID part. Last Octet is Host Id part.
For subnetting we borrow bits from Host ID. So we can borrow 0 bit, 1 bit, 2 bit …… upto 8 bits. So total 9 subnet masks can be possible.
Note: I have considered that only continuous bits can be assigned to subnet bits.