A convex lens produces a real image m times the size of the object.  What will be the distance of the object from the lens?

• A

  $\left(\frac{\mathrm{m}+1}{\mathrm{m}}\right)\mathrm{f}$

• B

  $(\mathrm{m}-1)\mathrm{f}$

• C

  $\left(\frac{\mathrm{m}-1}{\mathrm{m}}\right)\mathrm{f}$

• D

  $\frac{\mathrm{m}+1}{\mathrm{f}}$