valid SQL constraints

Hi, I need help with this question. I am not sure which one is the right answer. ATTACHMENT PREVIEW Download attachment

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Please selectthe correct answer and Check it! to have your answer
assessed. If you are wrong, you will see the correct answer
highlighted: Select the list nflhat contains only valid SQL constraints:
0 NOT NULL , API KEY , DEFAULT , PRIMARY KEY
O PRIMARY KEY , SERIAL KEY , IIIJT l’lULL , HJREIGIl KEY O lll]T NULL , FOREIGN KEY , PRIMARY KEY