 What best describes the overall structure of Captain Hannah's dialogue when recounting his time caring for the marocca plants?
Captain Hannah climbed painfully down from the Delta Crucis , hobbled across the spaceport to where Beulah and I were waiting to greet him and hit me in the eye. Captain Hannah had lost the Look of Eagles. I only drink rhial when I've been exposed to Captain Hannah. But when I offered them a sizable piece of cash plus a perpetual share of the profits for letting us take a load of marocca plants to Gloryanna III, they relented and, for the first time in history, gave their assent. "When I left, marocca was growing like mad," said Captain Hannah. You know that marocca takes a very special kind of environment. Bright sun most of the time—that means an almost cloudless environment. But our tests showed that the plants had enough tolerance to cause no trouble in the trip in Delta Crucis ." "Your tests were no good," agreed the captain with feeling. "You'll remember that I warned you that we should take some marocca out into space and solve any problems we might find before committing ourselves to hauling a full load of it?" asked Captain Hannah. If we had gone through all of that rigamarole, we would have lost the franchise. I almost asked him why he had been barricaded in the bathroom of the Delta Crucis , but I figured it was safer to let him tell me in his own way, in his own time. And by the time I had lined up for Gloryanna and Jumped, I figured, like you said, that the trip would be a cakewalk.
 A problem-solution structure.
 An argument and supporting details along with counterclaims structure.  A catchphrase followed by explanations structure.  A purpose and explanation structure.  A problem-solution structure.