Which of the following was ruled to be a violation of the separation-of-church-and-state princile of the First Amendment?

Question

A. Decorating city streets with stars and trees during the Christmas season.

B. Exemption of religious property from taxation.

C. Placement of a Ten commandment monument in a state courthouse.

Answer 1

http://www.cnn.com/2003/LAW/11/04/scotus.tencommandments/

Answer 2

Thanks