$(2$ marks$)$

c$.$Following the exchange above, Alice receives another communication:

iii.B $->$ A: $\{$M$2,$ n$2\}$K$($A plc$)$

What two differences can you see in the format of communications ii and iii? In other words, differences in the structure of each communication $($and not just the change from M$1$ to M$2$ and from n$1$ to n$2).$

Can Alice open communication iii?

Should Alice trust the second communication from Bob $($communication iii$)?$ Why or why not?