Sentence B is the correct one. It is the only sentence using content to refer to satisfaction rather than objects or substances.
The narrator of the "Golden Cat" sees the cat as friendly and warm. The line "His face is one big golden smile, it measures round, at least a mile-" expresses happiness and joy.
Answer: It mostly depends on the situation.
Explanation: While with some topics such as accidents it's best to remember so as to not make the same mistake in the future and better yourself so it won't happen again. However, some situations which had benefited no one are sometimes just best left forgotten as there is nothing to be gained positively.
Focusing on structure should be it, because you are focusing on the minutiae of a subject, and using logical, and exact thinking to get the best outcome.