Final answer:
The latest time to call the East Coast from the West Coast is 5:00 p.m. PST, considering the 3-hour time difference.
Step-by-step explanation:
The question pertains to determining the appropriate latest time to call from the West Coast to the East Coast, considering the time zones in the United States. Since the Pacific Standard Time (PST) is 3 hours earlier than the Eastern Standard Time (EST), one must account for this difference when planning calls to avoid calling too early or late. When it is 5:00 p.m. on the West Coast (PST), it is already 8:00 p.m. on the East Coast (EST). Assuming that people generally do not appreciate calls late at night, a safe guideline might be to avoid calling past 8:00 p.m. EST, which means the latest one should call from the West Coast would be 5:00 p.m. PST.