When bas van erp was the athlete what was the quarterfinals?
CREATE TABLE table_18602462_21 (quarterfinals VARCHAR, athlete VARCHAR)
SELECT quarterfinals FROM table_18602462_21 WHERE athlete = "Bas van Erp"
### Context: CREATE TABLE table_18602462_21 (quarterfinals VARCHAR, athlete VARCHAR) ### Question: When bas van erp was the athlete what was the quarterfinals? ### Answer: SELECT quarterfinals FROM table_18602462_21 WHERE athlete = "Bas van Erp"