Read the timeline below and answer the question that follows. In the timeline above, the red circle highlights a symbol that indicates a break in the timeline. Why do we use this symbol in timelines?

a. To show that a new century has started.
b. To indicate that a period of history is lost or unknown.
c. To help save space and allow more time to be shown.
d. To show that a date occurs on or after year 1 on the Latin calendar.