From the _____ look on his face,I know he has failed in the exam.   [ ]

A. disappointing    

B. disappointed      

C. disappoint        

D. disappoints

某县法院，对6名让未成年学生辍学打工的家长做出处罚决定，并要求他们无条件地让子女返校读书。这表明义务教育具有[ ]

A．伸缩性

B．强制性

C．普遍性

D．免费性