题目如图,ABABAB、CDCDCD是⊙O\odot O⊙O的弦,且AB=CDAB=CDAB=CD,若∠BOD=84∘\angle BOD=84^{\circ}∠BOD=84∘,则∠ACO\angle ACO∠ACO的度数为( )A.42∘42^{\circ}42∘B.44∘44^{\circ}44∘C.46∘46^{\circ}46∘D.48∘48^{\circ}48∘知识点:圆周角定理I章节:图形的性质 / 圆