Bob Gerard Racing มีนักแข่งกี่คน?ไม่จำเป็นต้องใช้โต๊ะทั้งหมด
How many drivers did Bob Gerard Racing have?It is not neccessary to use all the tables.
 table_21977627_1:  driver [ VARCHAR]  entrant [ VARCHAR] 
SELECT COUNT(driver) FROM table_21977627_1 WHERE entrant = "Bob Gerard Racing"