Final answer:
The Benjamin Franklin 1754 political cartoon 'JOIN, or DIE' symbolizes the necessity for American colonial unity under the Albany Plan of Union to withstand external threats, Hence, the correct answer is option (C).
Step-by-step explanation:
The political cartoon by Benjamin Franklin from 1754, depicting a snake cut into pieces with the message "JOIN, or DIE," is a piece of historical propaganda that advocates for the unification of the American colonies. The correct answer to the student's question about what the cartoon's meaning best explains is option c, It encourages the Plan of Union to protect against threats. This powerful imagery was used to stress the importance of the colonial unity and convey the idea that if the colonies did not unite under the Albany Plan of Union, they would be as vulnerable as a disjointed snake, unable to survive.
The cartoon symbolized the imperative for the colonies to join together to form a strong, cohesive unit capable of withstanding external threats, particularly from the French and Native American forces during the period of imperial conflicts leading up to the French and Indian War.