Final answer:
Parliament described itself as 'humbly' addressing King Charles in the English Petition of Rights as a way to flatter and appease the king while presenting demands, maintaining respect and minimizing conflict.
Step-by-step explanation:
The reason Parliament used the term when addressing King Charles in the English Petition of Rights was A. As a form of flattery to appease the king. The language of the time, especially in political documents, often included such terms of deference to convey respect and to reassure the monarch of the parliament's loyalty despite bringing forth grievances or requests.
Key events such as the execution of King Charles I and the shifting balance of power between the monarchy and Parliament are evidence of the ongoing struggle for governance and the eventual establishment of a constitutional monarchy, where Parliament held significant power, including control over the revenue.