听力原文： University of Maryland basketball coach Lefty Dresell resigned, another victim o

f the cocaine-induced death of basketball star Len Bias. Dresell's resignation came as no surprise. In recent weeks, advisors to Maryland Chancellor John Slaughter and some members of the Board of Regents were pushing for Dresell's removal. This morning, at Maryland's Cole Field House, Dresell made it official. "l want to announce that I am stepping down as the head basketball coach at Maryland. I will remain at Maryland in the position of Assistant Athletic Director. The university has agreed to honor the financial terms of my contract, which has 8 years remaining." Dresell coached basketball at Maryland for 17 years, but following Bias's death, Dresell told a Grand jury that he ordered an assistant to remove evidence of drug use from Bias's room, and subsequent revelations that his players were having academic problems proved to be Dresell's undoing.

What was a cause of Lefty Dresell's resignation？

A．Some of his players' deaths.

B．His methods of coaching.

C．His players cocaine use.

D．His players' academic problems.