Final answer:
George Washington set the precedent for presidential term limits by not running for a third term, which was later formalized by the Twenty-Second Amendment in 1951.
Step-by-step explanation:
The precedent that George Washington set by refusing to run for a third time is a. Presidential term limits.
Washington's decision established an unwritten custom that future presidents adopted, voluntarily limiting themselves to serving two terms in office.
This precedent was eventually codified into law with the ratification of the Twenty-Second Amendment in 1951, which formally limited the presidency to two terms.