Good afternoon! Please tell me who exactly can sign off on a requirement to reach 2nd class. Is it any responsible adult not related to the scout? Thank you!

Renee - generally all rank advancement requirements are signed off under the authority of the Scoutmaster and his/her delegates, which could be an Assistant Scoutmaster, Troop Guide, or long-term camp leader. It would be very unusual for requirements to be signed off by anyone else without prior approval/delegation of that authority from the Scoutmaster. Scoutmasters have ultimate responsibility for rank advancement and the Troop Committee has the same for merit badges.

Additionally, some troops allow Scouts who are at least First Class to sign off as well.