Refer to the "Jeff Bezos and Amazon" video: According to the Author's Guild, Amazon had been buying books at $$12-$$$13$ wholesale and selling them at $\_\_\_\_\_$ on the Kindle.

Group of answer choices

$$9\mathrm{.}99$

$$7\mathrm{.}50$

$$11\mathrm{.}99$

$$5\mathrm{.}25$

$$2\mathrm{.}50$