2. The method of claim 1 , wherein performing the class-narrowed type-restricted answer lookup comprises: selecting a class within the set of classes; identifying a set of entities in a topology connected to at least one entity in the question that are at most a predetermined number of hops from the at least one entity in the question and are of the selected class; and adding the set of entities to the set of candidate answers.
2. The method of claim 1 , wherein performing the class-narrowed type-restricted answer lookup comprises: selecting a class within the set of classes; identifying a set of entities in a topology connected to at least one entity in the question that are at most a predetermined number of hops from the at least one entity in the question and are of the selected class; and adding the set of entities to the set of candidate answers. 4. The method of claim 2 , wherein selecting the class comprises identifying a class within the set of classes having a highest frequency value and selecting each class within the set of classes having a frequency value greater than a threshold, wherein the threshold is a function of the highest frequency value and a tuning parameter.