A colleague gives you two tubes containing membrane fractions from an animal cell lysate. One tube ...

A colleague gives you two tubes containing membrane fractions from an animal cell lysate. One tube contains the plasma membrane fraction, and the other tube contains the mitochondrial inner membrane fraction, but the tubes are not labeled.
 
  When you analyze the macromolecule composition of the samples, you are confident that the second tube contains the mitochondrial fraction, because the sample has
  A) a higher ratio of cholesterol to phospholipids.
  B) a higher protein to lipid ratio.
  C) a lower protein to lipid ratio.
  D) more carbohydrate in glycoproteins.
  E) more GPI-anchored proteins.