Calculate the total time required to transfer a $1400$ kB file in the following cases, assuming an RTT of $200$ ms$,$ a packet size of $4$ kB data, and an initial $4\backslash$times RTT of $$handshaking$$ before data are sent.

a$.$ The bandwidth is $1\mathrm{.}7$ Mbps$,$ and data packets can be sent continuously.

b$.$ The bandwidth is $1\mathrm{.}7$ Mbps$,$ but after we finish sending each data packet, we must wait one RTT before sending the next.

c$.$ The bandwidth is $1\mathrm{.}7$ Mbps$,$ but after we finish sending each data packet, we must wait three RTTs before sending the next.

d$.$ The bandwidth is double $(3\mathrm{.}4$ Mbps$),$ and after we finish sending each data packet, we must wait one RTT before sending the next.