How should a PM manage a difficult stakeholder when it would be mandatory to have their buy$-$in$,$ such as a senior manager in a department directly impacted by the project$$

a$.$ The PM should instead focus their time on other mandatory stakeholders who will support the project

b$.$ The PM should put effort into uncovering the source of difficulty with the stakeholder to get their support

c$.$ The PM should engage the stakeholder to try to discover the root cause of the lack of support

d$.$ The PM develop a plan of action to get the stakeholder involved and supporting the project

e$.$ The PM should assign responsibilities from the WBS work package activities to motivate the stakeholder to get more involved in the project

f$.$ The PM should solicit the support of the project sponsor to get the stakeholder to support the project