Barotrauma - ok it’s when trapped gas can't
escape, causing pain.
So,....firstly the question asks about the middle
ear - no sinus there so can't be b) even though as a statement on its own it is
true, that's the gotcha.
a) less
likely as barotrauma most severe in ears on descent
due to increasing rate of increase in pressure.
c) it can
happen but it’s not the highest on the list and isn't expected so that leaves
d) barotrauma most likely in descent for reasons stated
above and the implication of the respiratory infection is that they have a cold
so blocked eustachian tube etc...