SQL & PL/SQL :: Privilege - Just Drop Special One Table?

There two users a and b,and the table b.test_part.And one procedure under a ,text like below:

create or replace procedure a.sp_test
is
vs_sqls varchar2(32767);
begin
vs_sqls:='alter table b.test_part truncate partition p_day';
execute immediate vs_sqls;
end;

now,i have to grant drop any table to a.but in fact,i prefer to drop the special one table "b.test_partany" rather than any other table.how ? no by trigger!