男性，60岁。摔伤致左髌骨下极粉碎性骨折2天。X线检查显示髌骨下极粉碎成4个小骨块。首选的治疗方法是（）

A.手法复位石膏外固定

B.切开复位张力带钢丝固定

C.切开复位钢丝环扎固定

D.髌骨下极切除、髌韧带重建术

E.髌骨切除术

（） are individuals and organizations that are actively involved in the project, or whose interests may be affected as a result of project execution or project completion.

A.Project managers

B.Project team members

C.Sponsors

D.Project stakeholders