A imo. Had something like this in a mock and it was always strategic goals, not just corralling multiple projects or aligning departments (that's more program management). Portfolio management is about direction at the org level. But if contract details highlighted inter-department stuff, I could see why folks say C. Pretty sure A is safest per PMI.
Why wouldn't C be right if the contract specifically calls out that departments need to be aligned? Most PMI material puts A as the key skill when the role is more strategic, but if the question was about cross-department synergy, wouldn't that make C just as valid?
C is tempting if the focus was just on departments, but portfolio manager is about bigger-picture strategy. I think A is better since portfolio work goes beyond managing just multiple projects or departments. Open to other views if someone thinks C fits better.