What should the project manager do first to ensure team adherence to the ground rules?

An experienced project manager is managing a multi-million dollar agile project. The project manager communicates the ground rules to the team but after 12 iterations, the project manager starts noticing that some team members are not following the ground rules.

What should the project manager do first to ensure team adherence to the ground rules?
A . Schedule a meeting with the project team to reinforce the ground rules.
B. Notify the project sponsor about this behavior and ask the sponsor to take disciplinary action
C. Contact human resources to request a written warning letter be sent to team members not following the ground rules.
D. Ask the functional manager to replace team members not following the ground rules

Answer: A