How many atoms of helium gas are required to fill a balloon with a diameter of 33 cm at 18°C and 1.761 atm?

a) 1.2 x 10²³ atoms

b) 2.5 x 10²⁴ atoms

c) 5.0 x 10²⁴ atoms

d) 1.0 x 10²⁵ atoms