$A$ thin convex lens and a thin concave lens are kept in contact and are co-axial. Which of the following statements is correct for this combination of two lenses?

• A
  behaves as a concave lens if $|f_{\text{convex}}| > |f_{\text{concave}}|$
• B
  behaves as a concave lens if $|f_{\text{convex}}| < |f_{\text{concave}}|$
• C
  behaves as a convex lens if $|f_{\text{convex}}| > |f_{\text{concave}}|$
• D
  Focal length of the lens system will change if the positions of two lenses are interchanged