电力二次系统的安全防护主要针对网络系统和基于网络的生产控制系统，重点强化边界防护，提高内部安全防护能力，保证（）及重要敏感数据的安全。

Last week a production worker had gross earnings of $390.00. If she worked more than 40 hours last week and was paid 1.5 times her regular hourly rate for each hour worked in excess of 40 hours, how many hours did she work last week ？（）
(1)If she had worked 4 more hours last week, her gross earnings would have been $435.00.
(2)Her regular hourly rate last week was $7.50.

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.