Your boss wants you to design subnets to support a new office. the office has three floors and each floor should be a subnet. • the net id for the entire site is 100.10.172.0/24 • the lan on the first floor must be able to support at least 50 hosts. • the lan on the second floor must be able to support at least 25 hosts. • the lan on the third floor must be able to support at least 10 hosts. • you must have one unused subnet for future expansion a. design the subnets (showing the mask and the first and last addresses in each subnet) using variable length subnet masks. [assume the address blocks include addresses where the host ids are all zeros and all ones.] b. how many addresses are left for the unused subnet