对数据库libinfo中数据表reader施加表级读锁的语句是（） A: LOCKreader READ; B: LOCKTABLESreader WRITE; C: LOCKTABLESreader READ; D: LOCKreader WRITE;

对角色student_role授权，其权限是对数据库libinfo中图书信息表book_info具有查询权限，则该授权语句是（ ） A: grant select on student_role to libinfo.book_info; B: grant select on libinfo.book_info to student_role; C: grant update on student_role to libinfo.book_info; D: grant all on student_role to libinfo.book_info;