Final answer:
D) Weeks
Step-by-step explanation:
The time length description considered synoptic scale is D) Weeks.
The synoptic scale is a term used in meteorology to describe weather phenomena that cover a large area, typically ranging from several hundred kilometers to thousands of kilometers. Synoptic-scale weather systems, such as low-pressure systems and high-pressure systems, can persist for several weeks.
Seconds, minutes, and even days are much smaller time units and do not typically represent synoptic-scale phenomena.