A website offers free shipping to customers who order at least $75 dollars worth of merchandise. Della is ordering 2 flashlights at $10.00 each and plans to order packs of $5.00 batteries until her total is at least $75. Which statement best describes how many packs of batteries she must order to qualify for free shipping?
A. 11 or more
B. 13 or more
C. 15 or more
D. 19 or more