What is A.C and B.C mean?

Question

In social studies regarding the years on how the counted they years.

Answer 1

A.D. (instead of A.C.) means Anno Domini, or years "after christ". B.C. is years "before christ". Most scientists and historians today, however, use B.C.E. (Before the common era) or C.E. (Common era). This year is 2019 C.E. OR 2019 A.D.