Hillary makes two transactions while at the mall:

• She returns an item to get $15 back at one store.
• She buys an item for $15 at another store.

Which is a correct description of the two quantities that represent these transactions?

A
The quantities have the same magnitude, but different signs.

B
The quantities have the same sign, but different magnitudes.

C
The quantities have different magnitudes and different signs.

D
The quantities have both the same magnitude and the same sign.