【名词&注释】
执法人员(law enforcement officials)、孵化期(incubation period)、行政处罚决定书(written decision of administrativepenal ...)、身份证件(authenticity of identity cards)、听取当事人
[单选题]鸡的孵化期是()天
A. 21 B. 28 C. 17~18 D. 30~32