听力原文： The government of Canada intends to recall its ambassador from Iran to protest the abrupt end of a murder trial. An Iranian intelligence agent was on trial for the killing last year of a Canadian-Iranian journalist. Canadian Foreign Minister Bill Graham said Sunday's decision by a Teheran court to end the trial is as he put it a denial of justice. Last week, Canada recalled its ambassador to protest Iran's refusal to allow observers at the trial.
Canada will call back its ambassador because the Teheran court

A. ended the trial suddenly
B. did not do justice
C. cleared the agent
D. changed the judges