Which of the following is an appropriate description of the mapping between the relational model and relational databases as its implementations?

Which of the following is an appropriate description of the mapping between the relational model and relational databases as its implementations?

1. a) A domain is mapped to a character type or a character string type.
2. b) A relation is mapped to a table
3. c) Attributes and columns are ordered from left to right
4. d) Neither tuples nor rows have duplicates