In SQL the statement select*from R, S is equivalent to:(a) Select * from R natural join S(b) Select * from R cross join S(c) Select * from R union join S(d) Select * from R inner join S

(b) Select * from R cross join S

Explanation: The SQL query command, Select * from R, S selects each rows from table R and merges combines it with each row of table S such that the number of columns increases. The merging could be said to be horizontal in nature since it results in an increased number of data columns. The Cross join method produces the same exact result with the output all columns in both tables (R and S). The inner join combines rows in tables as well but requires that both tables have a matching column values. The union join merges data the data in both tables vertically and will not produce the same output as the SELECT * FROM R, S statement.