Which of the Following Findings Provides the Most Sound Support

Which of the following findings provides the most sound support for the assertion that we learn aggression by observing others and imitating them?

A) Children who watch an adult assault a "bobo" doll will imitate that behaviour in the laboratory.
B) Abusive parents were often themselves abused when they were children.
C) Incidents of violence or threats of violence have occurred in high schools within weeks of each other.
D) Suicide rates increase after excessive news coverage of grisly suicides.
E) Spectators at a boxing match are more aggressive than those at a tennis match.