Adapted from A Jolly Fellowship by Frank R. Stockton

I was sitting on the deck of a Savannah steam-ship, which was lying at a dock in the East River, New York. I was waiting for young Rectus and had already waited some time, which surprised me, because Rectus was a very prompt person, who rarely kept people waiting. But it was probably impossible for him to regulate his own movements this time, for his father and mother were coming with him, to see him off.
I shall never forget how I first became acquainted with Rectus. About a couple of years before, he was a new boy in the academy at Willisville. One Saturday, a lot of us went down to the river to swim, and our favorite place was near an old wharf, which ran out into deep water, and a person could take a good dive there, when the tide was high. I was a good swimmer and could dive very well, but I was also learning to swim under water and had not done very much in that line at the time. So I took a dive from a post on the end of the wharf, and then turned, under water, to swim in shore. I intended to try to keep under until I got into water shallow enough for me to touch bottom, and walk ashore, and after half a dozen strokes, I felt for the bottom and my feet touched it. Then I raised my head, but I didn't raise it out of the water—it struck something hard.
In an instant, I knew what had happened. There was a big barge lying by the side of the wharf, and I had gotten under that! It was a great flat thing, ever so long and very wide. I knew I must get from under it as quickly as I could. I must have been wading up and down the length of the thing. I was bewildered. But just then, I saw through the water someone, not far from me, reaching his hand toward me, and I staggered towards him, and in a moment my hands went out of water, just at the side of the barge. I stood up and could finally see the shore. The boy who was standing by me was Rectus. He did not have that name then, and I didn't know him.

Which sentence from the passage expresses an idea that should be included in a summary?
A. I shall never forget how I first became acquainted with Rectus.

B. I was sitting on the deck of a Savannah steam-ship, which was lying at a dock in the East River, New York.

C. The boy who was standing by me was Rectus.

D. About a couple of years before, he was a new boy in the academy at Willisville.