Need help!

Consider: SELECT 1 FROM (SELECT "B") AS A;* What is the output, and what is the part between () called? O A B, nested query O B, nested query O B, subquery 1, subquery O A, secondary query Consider: SELECT * FROM (SELECT "B") AS A JOIN (SELECT "C") AS D;* What is the output? Is this a Cartesian Join? "D" is named an ...? What does do or mean here? O BIC, yes, alias, select all columns produced by the query O , no, alias, select all columns produced by the query O B+C, no, constructor, select columns from all subqueries O *yes, constructor, select complete result set