Answer these questions about IP address space: (a) What is the theoretical maximum address space for a 32-bit address, such as that used by IPv4? (Ignore the fact that some addresses aren't usable or available, just calculate the theoretical maximum number of addresses) (b) Now suppose the address is expanded to 40 bits (for example, adding a fifth number from 0 to 255 to the existing four). How much address space does that result tin? (c) Now consider the 128-bit address of IPv6. How much theoretical address space is that? (d) Briefly speculate as to why you think the designers of IPv6 went to such lengths to make so much address space.