Adaface Sample Oracle SQL Questions

Here's a proposal for SALES table in Oracle SQL:

Of the following statements about creating SALES table and storing data, which are true?

A: The CUST_STATUS column would store exactly one character
            B: The SALE_VALIDITY column would have a maximum size of one character
            C: The CUST_CREDIT column would be able to store decimal values
            D: The SALE_VALIDITY column would give an error

Of the following CREATE ORACLE SQL queries, which all would create "users" table with columns user_id and login_id as unique and not null?