Final answer:
Typically, one authorized official, usually a merit badge counselor or Scoutmaster, is allowed to sign the completion on a Boy Scouts blue card. Local troop policy or Boy Scouts of America guidelines should be consulted for specific rules.
Step-by-step explanation:
The question of how many authorized officials are allowed to sign a completion on the blue card seems to be related to Boy Scouts America's merit badge process, often encountered in the context of Social Studies, as it deals with organizational rules and procedures. Each Boy Scouts troop may have different rules, but commonly, one authorized official, typically a merit badge counselor who is registered and has been approved by the Boy Scouts of America, is responsible for signing off on the completion of the blue card. This can also be the Scoutmaster or another designated leader within the troop. It is best to check with the local troop's policy or with the Boy Scouts of America guidelines to determine if more than one signature is required or permitted.