The Cash table below contains seven attributes. Which of those could possibly be foreign keys? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer. Any boxes left with a question mark will be automatically graded as incorrect.)

Cash Receipt:

Remittance Advice #	Date	Amount	Customer #	Check #	Invoice #	Cashier #
RA-220	11/02/2016	2549.90	C-12	201	S-101	E-13345
RA-278	11/10/2016	699.90	C-5	1457	S-108	E-13347
RA-276	11/30/2016	1209.70	C-9	392	S-107	E-13345
RA-289	11/30/2016	949.95	C-28	2558	S-105	E-13346

• Customer #unanswered
• Check #unanswered
• Cashier #unanswered
• Amountunanswered
• Dateunanswered
• Remittance Advice #unanswered
• Invoice #