Knowing their son failed in the exam, the parents stood there, ________.

A．looked disappointed

B．looking disappointed

C．looked disappointing

D．looking disappointing

（）投交封装完好的特快专递邮件，如收件人要求当面开拆邮件验视内件后再办理签收手续时，投递员应婉言拒绝。如收件人一再坚持，则将邮件转为局内投交，由收件人到局自行领取。