14. What is a foreign key? a) A foreign key is a primary key of a relation which is an attribute in another relation relations b) A foreign key is a superkey of a relation which is an attribute in more than one other c) A foreign key is an attribute of a relation that is a primary key of another relation schema d) A foreign key is the primary key of a relation that does not occur anywhere else in the 15. Table: promotions Promo_id Promo_name Com_name Promo_category Promo_cost 1 Flyer CVS 1 1000 Signage Target 1000 W N Radio Walmart 2 1500 4 Web Wegmens 1500 Create a report of unique promotion costs in each promotion category. SELECT DISTINCT promo_category, promo_cost FROM promotions ORDER BY 1; SELECT UNIQUE promo_category, promo_cost FROM promotions ORDER BY 1; SELECT DISTINCT promo_category, promo_cost FROM promotions GROUP BY promo_id; d) SELECT UNIQUE promo_category, promo_cost FROM promotions GROUP BY promo_id; mohoq of elinammon ashivong JOd .ES 16. What command is used to create a new table? a) CREATE TABLE b ) BUILD TABLE sendero C ) GENERATE TABLE wodn to onion (b d) None of the above 17. Which of the following commands are used to put a restriction on the number of rows returned from a query? a) LIKE b) LIMIT C) WHERE d) GROUP BY enos of bean voll 18. Conditionally retrieval of rows from a table with SELECT, which clause is used? a) Where benoliner silt to win b) Having c) Group by d) Order by keyword eliminates duplicate rows from the result of a SELECT stat 19. The