The first question is incomplete.
But it is actually given somewhere, Let us assume it is classful classification.
Then, given IP belongs to class B.
Generally, In class B, Network id = 16 bit, host id = 16 bit ( without any subnetting)
a) Then maximum possible subnet is ( 2 ^ 16) and each subnet has its only one Host. and the minimum is 1 which has (2^ 16), host.
b) Possible host in each subnet in range of ( 1 to 2^16)
c) 171. 150. 0.0
I try to give an answer as much as possible.
If anything wrong after taking an assumption, comment below.............!