Wood pellets are produced from the waste sawdust of lumber and paper mills. Home-heating

Wood pellets are produced from the waste sawdust of lumber and paper mills. Home-heating stoves burning these pellets can heat homes directly, instead of relying on other energy sources. Heating your home with wood pellets is :

(a) sustainable, less polluting, and about 3 times as efficient as heating a home using electricity from a coal-fired power plant. 

(b) sustainable, slightly more polluting, and is about 30% more efficient than using electricity from a coal-fired power plant. 

(c) not sustainable but is less polluting and is about as efficient as using electricity from a coal-fired power plant. 

(d) not sustainable and actually pollutes more than using electricity from a coal-fired power plant.