Which from of power is the LEAST effective from the project manager's viewpoint in terms of influencing functional manager

A．Formal powe

B．Expert powe

C．Penalty powe

D．Referent powe

进行锅炉底部联箱加热时，要使加热蒸汽压力（）MPa，并逐个缓慢开启各水冷壁下联箱的蒸汽加热门。