A lava tube is a tunnel inside hardened lava, where molten lava can flow. A particular lava tube can be modeled as a right circular cylinder with a diameter (d) of 6.6 feet and a length of half a mile. The lava flows from a reservoir filled with 8.8 x 10¹⁰ cubic feet of molten lava. (Note: 5, 280 feet = 1 mile.) Modeling the lava reservoir as a sphere, what would be its approximate radius, in miles?
a. 0.5 mile
b. 8.8 miles
c. 2, 643.3 miles
d. 2, 759.3 miles