女性，45岁，左胫腓骨下1/3开放性骨折，行清创缝合石膏固定治疗，3个月后局部仍有压痛，X线显示骨折线尚存在，有少量外骨痂，骨折对位良好，下列哪项是导致骨折延迟愈合或不愈合的主要因素

A．年龄大
B．开放性骨折
C．骨折部血液供应差
D．软组织损伤
E．石膏固定

When you read the sailing directions, you should notice that this is one of a series of publications produced by the（）which should be consulted by users of Admiralty Charts.

A.UK Hydrographic Office

B.IMO

C.International Hydrographic Organization

D.International Association of Classification society