In an essay it should only be one I'm pretty sure, but in a narrative as many as it takes to explain a lesson learned. If you were writing a book your conclusion would be whatever comes to you and whatever you feel the characters would do/say/feel.
If you would post the lines i could definitely help you with your work...<span />
The answer is A because before but there is always a coma
2, 4, and 5 have to be the answer by process of elimination
Edit: 4 "he followed out his original design," is incorrect but 2 "Endowed with commonsense, as massive and hard as blocks of granite" and 5 "On the score of delicacy, or any scrupulousness which a finer sensibility might have taught him, the Colonel, like most of his breed and generation, was impenetrable." are.