The human resource (HR) department of Avamtul, a television channel, posted a job requirement on the company website. The post invites engineers with any specialization who have done broadcast engineering apprenticeships to apply for the post of broadcast engineer in the company. In the context of HR planning, which of the following concepts does this scenario best illustrate?
选项：

A: Job description
B: Employee separation
C: Job specifications
D: Employee selection