Assertion. There must be some identical columns in tables in order to get cartesian product.

Reason. The cartesian product returns all possible combinations of rows from the participating tables.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

A is false but R is true.

Explanation
The cartesian product does not require any identical columns, it pairs each row from one table with every row from another table, creating all possible combinations of rows and returning them.