tbh, I've seen your comments in the discussion and I believe you could definitely do better than a 169

I'm interested too!

Even if it did attack the premise, that would be similar to choice B, which attack the first sentence. It still "weakens" the argument by contradicting information presented. However, if this was NOT an except question, you wouldnt pick that answer because it attacks the premise/Goku rather than his beam/Kamehameha. The reason E is still better is because if you "null" either foolishness or historical accident, the one not "nulled" will still be valid, and the conclusion will still apply -- therefore the argument will not be weakened as result.