Determine the phases present, the compositions of each phase, and the amount of each phase in wt% for the following MgOFeO ceramics at 2000°C: 

(a) MgO-25 wt% FeO; 

(b) MgO-45 wt% FeO; 

(c) MgO-60 wt% FeO; and 

(d) MgO-80 wt% FeO.