下列图形最有可能是哪段代码执行后的结果?( )

A： import turtle turtle.forward(100) turtle.left(90) turtle.circle(50,180) turtle.down()

B： import turtle turtle.forward(100) turtle.left(90) turtle.circle(50,-180) turtle.down()

C： import turtle turtle.forward(100) turtle.left(90) turtle.circle(50,90) turtle.down()

D： import turtle turtle.forward(100) turtle.left(90) turtle.circle(50,-90) turtle.down()