Multiple-argument aggregate functions

You have a table ABC with columns a and b. You now want to use a multiple-argument aggregate function to display a in descending order of b. To do this, you have written the following two queries.

A:

SELECT string_agg(a, ‘,’ ORDER BY b) FROM ABC;

B:

SELECT string_agg(a ORDER BY b, ‘,’) FROM ABC;

Which of these queries is an incorrect way to implement the given objective?

Options

1. Only A
2. Only B
3. Both A and B
4. Neither A nor B