1. The Company database attaches each Dependent to exactly one Employee by using a primary key of ESSN (the ID of the employee who is the guardian for this dependent) and the first name of the dependent. Suppose we want to make the key more efficient by adding a SERIAL attribute and making that the new PRIMARY KEY. What is an error we have to watch out for? The current design of Dependent is: ESSN, dependent_name, sex, bdate, relationship, where the key is the pair (ESSN, dependent_name), and ESSN is also a foreign key referencing the Employee table a) There are no errors to worry about b) The new key might eventually get big enough to have a value equal to an SSN c) The ESSN could be NULL d) There could be more than one dependent of an employee with the same first name 2. For the best way to represent user and account information where a user can have multiple accounts, as the class has discussed these things so far, a) There should be separate User and Account tables where the Account table has a foreign key to the User table b) There should be separate User and Account tables where the User table has a foreign key to the Account table c) There should be a single UserAccount table with all information about users and accounts d) There should be separate User and Account tables, plus a third table with foreign keys to both the Account and the User tables.