Final answer:
The Continental Congress' Olive Branch Petition was effectively nullified by The Prohibitory Act, which declared the colonies in rebellion and cut off trade between the colonies and Great Britain.
Step-by-step explanation:
The publication that effectively nullified the Continental Congress' Olive Branch Petition to King George III was The Prohibitory Act. The Olive Branch Petition was a final attempt by the colonists to reconcile with the British crown and avoid further hostilities, but it was rejected by King George III. In response, the Prohibitory Act was passed by the British Parliament in December 1775, which declared the American colonies to be in a state of rebellion and cut off trade between the colonies and Great Britain.