听力原文： We do not know when man began to use salt, but we do know that it has been used

in many different ways throughout history. Historical evidence shows, for example, that people who lived over 3,000 years ago ate salted fish. Thousands of years ago, salt was used to keep the dead from decaying in Egypt. Stealing salt was considered to be a major crime during some periods of history. In the 18th century, for instance, if a person was caught stealing salt, he would be put in jail. History records that about ten thousand people were put in jail during that century for stealing salt. About 150 years before, taking more than one's share of salt was punishable as a crime. The offender's ear was cut off. Salt was an important item on the table of a king. It was traditionally placed in front of the king when he sat down to eat. Important guests at the king's table were seated near the salt. Less important guests sat away from it.

When did salt first begin to be used by man？

A．Over 3,000 years ago.

B．In the 18th century.

C．We don't know.

D．In the 16th century.