Final answer:
In a unionized workplace, if a grievance is filed during open labor negotiations, the key best step that HR should take is to option A: acknowledge the grievance and begin collecting facts regarding the matter.
Step-by-step explanation:
In a unionized workplace, if a grievance is filed during open labor negotiations, the key best step that HR should take is option A: Acknowledge the grievance and begin to collect facts regarding the matter.
When a grievance is filed, HR should take it seriously and start gathering information to understand the issue and determine the appropriate course of action. This may involve conducting an investigation, interviewing involved parties, reviewing relevant documents, and seeking input from supervisors or managers.