To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) Fifty - This option is incorrect because the names of the sons are Ten, Twenty, Thirty, Forty, and Larry. The name of the fifth son would not be Fifty.
Option B) Larry - This option is correct. Larry is the name of the fifth son, as mentioned in the question.
Option C) Forty - This option is incorrect because Forty is the name of the fourth son. The question asks for the name of the fifth son.
Option D) None - This option is incorrect because Larry is the name of the fifth son, as mentioned in the question.
Therefore, the correct answer is B) Larry. This option is correct because it corresponds to the name of the fifth son.