The API changes should provide both source and binary (71)for programs written to the original API. That is, existing program binaries should continue to operate when run on a system supporting the new API, In addition, existing (72) that are re-compiled and run on a system supporting the new API should continue to operate. Simply put, the API(73) for multicast receivers that specify source filters should not break existing programs, The changes to the API should be as small as possible in order to simplify the task of converting existing (74)receiver applications to use source filters. Applications should be able to detect when the new(75)filter APls are unavailable(e.g., calls fail with the ENOTSUPP error) and react gracefully(e.g., revert to old non-source-filter API or display a meaningful error message to the user).

空白处（74）应选择（）

A.multicast

B.unicast

C.broadcast

D.anycast

女性，70岁，双膝关节疼痛10年余，加重1年，行走较长距离后疼痛感加重。查体：双膝关节内翻，浮髌试验（-），双膝关节活动范围0°～10°～95°。X线片可见内侧关节间隙狭窄、周缘骨赘形成。

最有可能的诊断（）

A.骨性关节炎

B.类风湿性关节炎

C.强直性脊柱炎

D.化脓性关节炎

E.创伤性关节炎