I believe the tone is kind of sad. The mood the author wanted to make was sadness. He wanted you to image him when he was younger. (i hope this helped)
Let's work through the problem:
A: "And conclusion" doesn't sound correct, it's not proper grammar.
B: "And some conclusion" "Some" is improper and is not an option.
C: "The Conclusion" is correct; "the" in the sentence shows that it is "The Conclusion", not just "A conclusion".
Well we use today systems and back then systems
