We combined a convex lens of focal length f₁ and concave lens of focal lengths f₂ and their combined focal length was F.  The combination of these lenses will behave like a concave lens, if

• A

  ${\mathrm{f}}_1>{\mathrm{f}}_2$

• B

  ${\mathrm{f}}_1<{\mathrm{f}}_2$

• C

  ${\text{f}}_1={\mathrm{f}}_2$

• D

  ${\mathrm{f}}_1\le {\mathrm{f}}_2$