题目如图,∠AOD=75∘\angle AOD=75^{\circ}∠AOD=75∘,∠COD=30∘\angle COD=30^{\circ}∠COD=30∘,若OBOBOB平分∠AOC\angle AOC∠AOC,则∠AOB=( )\angle AOB=\left(\ \ \right)∠AOB=( )A.22.5∘22.5^{\circ}22.5∘B.25∘25^{\circ}25∘C.30∘30^{\circ}30∘D.3.5∘3.5^{\circ}3.5∘知识点：角的定义章节：未标注
