A company would like to implement two-factor authentication for its vulnerability management database to require system administrators to use their token and random PIN codes. Which of the following authentication services accomplishes this objective?

Which one of the following statements is true about primary keys?

(A) A column of names is usually a good choice for use as a primary key. (B) Only a single record can be used as a primary key. (C) Social Security numbers are never used as a primary key. (D) A primary key is used to uniquely identify records in a table.

A/An ____________ can change the length while the program is running.

a. Array b. ArrayList c. Type parameter d. None of the above