Your ISP assigned you a full class B address space. From this, you need at least 300 sub-networks that can support at least 50 hosts each. Which of the subnet masksbelow are capable of satisfying your needs?()
A、255.255.255.0
B、255.255.255.128
C、255.255.252.0
D、255.255.255.224
E、255.255.255.192
F、255.255.248.0