$[10$ points$]$ Consider the problem of recovering from host crashes $($i$.$e$.,$ Fig. $6-18$ of textbook;

see below$).$ If the interval between writing and sending an acknowledgement, or vice versa,

can be made relatively small, what are the two best sender$-$receiver strategies, for

minimizing the chance of a protocol failure? Explain why.

Please refer to attached figure in screenshot.