Is carbon a satisfactory reducing agent for all metal oxides? Give reasons.

The roasted or the calcined ore is reduced to the metal by using a suitable reducing agent. The choice of the reducing agent depends on the reactivity of metal. If the metal to be extracted, is very reactive like the alkali metals $(Na,K)$ and alkaline earth metals (Ca, Mg) and aluminum, then the reduction of the oxide can be done only by the electrolytic method.

The oxides of the less reactive metals such as zinc, iron, copper, lead, tin, manganese, chromium can be reduced by a number of reducing agents such as reduced by a carbon, carbon monoxide. 

So carbon satisfactory reducing agent for all types of metal oxides.