Based on the text, the inference that is most likely supported is:
B. Although school was not Samuel's favorite, it helped him become a successful writer.
This option suggests that while Samuel Langhorne Clemens (Mark Twain) may not have enjoyed school, the experiences and knowledge gained there contributed to his success as a writer, which aligns with what is generally known about his life and career. The other options may involve personal feelings or situations that are more subjective and may not be directly supported by the text.