如图6-5-1所示，圆a、b所在平面垂直地球的自转轴线，圆b的圆心就在地心处，圆c所在平面与地球自转轴线平行，则对环绕地球做匀速圆周运动的卫星而言（　　）

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图6-5-1

A．卫星的轨道可能是a

B．卫星的轨道可能是b

C．卫星的轨道可能是c

D．同步卫星的轨道只可能是b

During project execution, the customer authorizes and funds a scope change which requires a major change in the schedule. The baseline schedule （）.

A．now becomes the new schedule, including the changes, and the original baseline is disregarded

B．is still the original baseline but annotated to reflect that a change has taken place

C．is amended to reflect the scope change, but the original baseline is still maintained for post-project review

D．is meaningless since every schedule update changes the baseline