In relation to employment law:

(b) Explain the statutory provisions that apply when an employer wishes to modify the content of a labour contract, and the ways in which this may be implemented. (4 marks)

男性，65岁。1年前体检X线胸片无明显异常。刺激性咳嗽伴血痰1个月，近10天来呼吸困难。查体：气管左移，左胸廓下陷，叩实音，管状呼吸音，心界左移。胸片示左胸均匀一致的致密影，胃泡影上移。

确诊后首选的治疗方案是（）

A.大剂量青霉素及链霉素治疗

B.口服利福平

C.开胸探查与肺切除

D.胸腔闭式引流

E.胸腔穿刺