Given the following choices;
Monoclines
domes and basins
anticlines and synclines
horsts and grabens
The answer is domes and basins.
Domes are symmetrical anticlines hence their round shape. Vulcanic activity under the earth’s crust pushes up the portion of the crust. The overlapping folds of domes face inward. Basisn is the opposite of domes. They are symmetrical depressions of the earth’s crust and their overlaps face outward.