查询职称为讲师的姓名,年龄和性别,正确的语句是? A. db.teachers.aggregate([ {project:{"name":1,"age":1,"sex":1,"_id":0}} ]) B. db.teachers.aggregate([ {project:{"name":1,"age":1,"sex":1}} ]) C. db.teachers.find("prof":"讲师",{"name":1,"age":1,"sex":1}) D. db.teachers.find({"prof":"讲师","name":1,"age":1,"sex":1})