Avalley of rolling hills is an example of a.)monoclines b.)anticlines and synclines c.)horsts and grabens d.)fault-block mountains

I think the correct answer from the choices listed above is option B. A valley of rolling hills is an example of anticlines and synclines. Anticlines are folds in which each half of the fold dips away from the crest. Synclines are folds in which each half of the fold dips toward the trough of the fold.