255.255.255.252
The default subnet mask would be 255.255.0.0 for a class B address.
Since 157.54.4.201 falls in the class B address range the default subnet mask would be: 255.255.0.0 128 - 191 is a class B address.
If your address is not subnetted, then the default subnet mask would be used. For this class address, it would be 255.0.0.0
172.16.0.0. The first ip address within this subnet is 172.16.0.1
195.85.8.0 is a class C network. The subnet mask would be 255.255.255.0 and the network address is 195.85.8.0
The subnet mask would be 255.0.0.0 considering it to be class A address. you can check it by typing the IP address in the wireless network properties of IPv4 in your laptop.
If this is a default subnet mask, then it would be a class C subnet mask. If you are subnetting a network and this is not the default subnet mask, then it could be either a class A or class B.
The default subnet would be 255.0.0.0 (class A)
Since this is a class C address the subnet mask for the default would be 255.255.255.0. Other values could be:255.255.255.128 - 255.255.255.252
That would be a class E network, E networks do not have defines subnet masks or networks. Just a range (240.0.0.0 - 255.255.255.255).
255.255.254.0
Depends on your subnet mask. If you are talking about a classful addressing scheme in a class B, then the network would be 172.32.0.0