At first I chose letter B as the answer to question 21, but before analyzing and reading carefully I realized that the answer is letter C because answer C states “thoughtfully examine the possible causes” and that phrase reflects the part of the text that mentions the part they failed to do: "review the contributing factors in a considered manner”. That was the part they were missing, as they were focusing on "evaluate events" rather than looking at why everything happened. My mistake was misreading and misinterpreting the part that mentions “not rich or detailed enough” that actually means that their understanding of the events in the classroom was not detailed enough to support reflection, not that they could not describe the methods they used, so that answer would be discarded.