A small object is placed in front of a converging mirror with radius $R=7.50 \mathrm{~cm}$ so that the image distance equals the object distance. How far is this object from the mirror?
a) $2.50 \mathrm{~cm}$
b) $5.00 \mathrm{~cm}$
c) $7.50 \mathrm{~cm}$
d) $10.0 \mathrm{~cm}$
e) $15.0 \mathrm{~cm}$