The power to regulate interstate commerce is a power that is exclusively given to the American Government by the U.S. Constitution. The regulation of interstate commerce was a major issue during the times of the Articles of Confederation and was therefore an issue with the Constitutional Framers were sure to create in the new Constitution.
It falls every year on August 27, to mark the birthday of U.S. President Lyndon Baines Johnson. After Johnson died in 1973, the Texas State Legislature created a legal state holiday to be observed every year on August 27 to honor the 36th president of the United States, one of their state's native sons.
B. is the answer.