To retrieve Class 9 morning section students, which query is correct?

• aSELECT * FROM student WHERE class = 9 OR section = 'morning';
• bSELECT * FROM student WHERE class = 9 AND section = 'morning';
• cSELECT * FROM student WHERE class = 9, section = 'morning';
• dSELECT * FROM student WHERE class = 9 NOT section = 'morning';