On 6 July, at 1000 zone time, you cross the 180th meridian steaming westward. What is your local time?

Correct Answer: Option B — It is 1000, 7 July.

Crossing the 180th meridian (International Date Line) heading westward requires advancing the calendar date by one day. Therefore, 1000 zone time on 6 July becomes 1000 on 7 July.