Julie Owns a Gun and Has for Several Years

Julie owns a gun and has for several years. She is arrested for possession of a firearm within the city where she lives. The day following her arrest, the city passes a law making gun ownership of any kind illegal and punishable by a year in jail for the first offense. Julie is sentenced to one year and a day in prison. ​

A) Julie further contends that her conviction on the gun possession charge is a clear violation of the prohibition against ex post facto laws, which is guaranteed by  ___________ of the United States Constitution. ​
B) Article VII
C) Article IV
D) Article II
E) Article I