can anyone help me answer that

20. The attribute B is the attribute A if each value in column A determines one and only one value in column B. a. logically dependent on b. owned by c. determined by d. functionally dependent on 21. Any attribute that is part of a key is known as a a. key attribute b. logical attribute c. key determiner d. selector 22. If the attribute (B) is functionally dependent on a composite key (A) but not on any subset of that key, the attribute ( B) is fully functionally dependent on (A). a. foreign b. unique c. composite d. complete No data entry at all is known as a(n)--. a. nil b. null 23. c. empty d. zero 24. In the following table description. is the primary key PRODUCT (PROD CODE, PROD DESCRIPT, PROD PRICE, PROD ON HAND, VEND_CODE) a. PROD DESCRIPT b. PROD_CODE c. PROD PRICE d. PROD_ON HAND 25. A CUSTOMER table's primary key is CUS_CODE. The CUSTOMER primary key column has no null entries, and all entries are unique. This is an example of integrity. a. entity b. referential c. complete d. null