He oldest ___ in the world is the Roman Pantheon; the circumference of its dome is about 142 feet. A. concave B. configuration C. effigy D. rotunda

Both the height and diameter of the rotunda are 142 feet. I wonder if there's a typo here?

An effigy is a structure. Since the rotunda is 142 feet across, maybe that's it. The circumference is about 390 feet.