Which is the most accurate description of an atmospheric tank?

a. A storage tank designed to operate at pressures ranging from atmospheric pressure through 0.5 psig (3 kPa).
b. A storage tank designed to operate at pressures at or above 0.5 psig (3 kPa), but not more than 15 psig (100 kPa).
c. A storage tank or other vessel designed to operate at pressures above 15 psig (100 kPa).
d. A storage tank or other vessel designed to operate at pressures above 500 psig (3448 kPa).

A