二尖瓣狭窄第一心音亢进是因为

A．心脏开始收缩时，二尖瓣位置低垂
B．心脏开始收缩时，二尖瓣后叶关闭延迟
C．心肌收缩力加强
D．二尖瓣前叶增厚
E． * * 肌功能失调

Company XYZ has a fixed price contract to produce 10,000 widgets for a price of $100,000. An invoice will not be generated until all widgets are completed. The budgeted cost of manufacturing the widgets is $9 per widget. All widgets were to be completed by today. Unfortunately, the project is behind schedule, and only 9,000 widgets have been completed. Actual manufacturing costs to date are $90,000. In the sample scenario above, what is the cost performance index

A) 1.23.
B) 0.9.
C) 1.
D) 1.1.