I posted this question twice now, and I keep getting wrong answers, I wanted the candidates keys not the primary key. I already know std-id and email are candidates keys, but I'm not sure if (first-name,dept_id) is a candidate key or if there any other candidate keys. please, I just want the answers no explanation needed.

jiven the following schema for a student relation student-schema =( std_id, first_name, adviser_id, mail, dept_id) Where: std id is the student's id. first_name is the student's first name. adviser_id is the id of the student's adviser. email is the student's email address. dept_id is the id of the of the students's department. List all of the possible candidate keys for the Student-schema when ALL OF the following constraints are imposed. Note that since all of the constraints must hold, you should produce only one list. a. Each student will be represented by exactly one tuple. b. Each student has a unique id. c. No two students will have the same email address. d. No two students in a single department will have the same first_name. e. No two departments will have the same dept_id f. A department can have any number of students. g. A student will have only one adviser