"That afternoon I was sent out again to sell some goods to the soldiers. "
Explanation:
All but one are said in the first narrative, so you can rule the last one out. I believe this one is the answer, as it mentions the narrator being sent somewhere to sell to soldiers, which means that he is a merchant, or believed to be one.
After a long conversation and much planning, we at last decided that I should go through our lines the next night with a person known to the merchant."
