If Pat bought a tennis shirt with matching shorts, what was the cost of the shirt ？（）
(1)The total cost of the shirt and shorts was $20.
(2)The ratio of the cost of the shirt to the cost of the shorts was 2:3.

A．条件(1)充分，但条件(2)不充分．

B．条件(2)充分，但条件(1)不充分．

C．条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．

D．条件(1)充分，条件(2)也充分．

E．条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

话音质量分为几级？