In a retail store, the average (arithmetic mean) sale for month M was d dollars. Was the average (arithmetic mean) sale for month J at least 20 percent higher than that for month M ？（）
(1)For month M, total revenue from sales was $3,500.
(2)For month J, total revenue from sales was $6, 000.

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.

钻柱的疲劳破坏有（）破坏三种形式

A、纯疲劳、伤痕疲劳和腐蚀疲劳

B、纯疲劳、电化学疲劳和化学疲劳

C、纯疲劳、伤痕疲劳和电化学疲劳

D、应力疲劳、伤痕疲劳和腐蚀疲劳