Which among the following statements is $NOT$ true about Frenkel defect?

• A
  It occurs in ionic compounds with sizes of cations and anions almost equal.
• B
  The density of solid crystal and its chemical properties remain unchanged as no ions are missing from the crystal lattice as a whole.
• C
  The crystal as whole remains electrically neutral because equal number of cations and anions are present.
• D
  The ions of ionic compound must have low co-ordination number.