Q$\mathrm{.}2.$

a$.$ Suppose Host A sends two TCP segments back to back to Host B over a TCP connection. The first segment has sequence number $90$; the second has sequence number $110.$

i$.$ How much data is in the first segment?

ii$.$ Suppose that the first segment is lost but the second segment arrives at B$.$ In the acknowledgment that Host B sends to Host A$,$ what will be the acknowledgment number?