mysql基本语句三个简单考试问题！求助！

不太会（b）和（c）的后面两个
去年的考试题 复习用 希望大神给我指点迷津
谢谢

(b)
select count(registrationNumber),model
from car,rental
where car.registrationNumber=rental.registration
and
date='2015-01-06'
group by model

(c)
(I)select driverID,name
from driver
where age＞35
(II)select driverID,count(driver)
from driver,rental
where driver.driverID=rental.driver
group by driverID

select driverID,max(year(date))
from driver,rental
where driver.driverID=rental.driver
group by driverID