"My knife is sharper than your sword."
Translation:tajwIj jej law' 'etlhlIj jej puS.
You're right. As far as I can see, yan doesn't appear until the skill "Melee Weapons", which is nearly the last skill on the entire tree -- it should not be required as known here.
I've removed it from the "best" alternative while retaining it among the remaning alternatives.
I believe multiple-choice questions choose required correct answers only from the alternatives marked "best" (though they sometimes base their distractor sentences on other alternatives).
Thanks for notifying us about this!