which is your pen

题目

which is your pen
a .a red one and a blue one b.a red one or a blue one c.the red oneand the blue one d,the red one or the blue one
哪个对?请说明理由——

答案

D.用the表特指,用and谓语动词为复数,用or谓语动词为单数.
由题目则得D