Answer:
d. Both A and B
Step-by-step explanation:
Ribbed vaulting is an architectural element widely used in Gothic architecture buildings. It is a derivation of the so-called edge vault, which is distinguished by the use of structural diagonal ribs that support its weight and discharge it on composite pillars or polystiles) and to which they belong, and generally identified with them, the so-called warhead vaults (also referred to as crossover warhead vaults) and rib vaults (also referred to as rib vaults). This architectural element can be seen in Durham Cathedral and St. Etienne Cathedral.