subnetting

You have been given the 172.16.0.0 network. Your boss has tasked you with creating 250 subnets that allow for up to 254 hosts each. What subnet mask would you use to achieve this goal?
i need your assistance for this Question as if the ans is 255.255.255.0 then it would be 1 subnet instead of 250
please explain ?
thanks in advance

255.255.255.0 or /24
172.16.0.0 - 172.16.0.254
172.16.1.0 - 172.16.1.254
172.16.2.0 - 172.16.2.254
.and so on
.and so forth
172.16.255.0 - 172.16.255.254

Here is a great article on firewall.cx that explains why.

www.firewall.cx/networking-topics/protoc...etting-analysis.html