Read the sentence. Philadelphia has distinguished itself by preserving its old buildings and the incorporation of new structures. Which revision corrects the faulty parallelism? Philadelphia has distinguished itself by preserving its old buildings and incorporating its new structures. Philadelphia has distinguished itself by incorporating its new structures and the preservation of old buildings. Philadelphia distinguishes itself, preserves its old buildings, and the incorporation of new structures. Philadelphia has not only distinguished itself but also preserves its old buildings and incorporates new structures.