Cobalt $(III)$ chloride forms several octahedral complexes with ammonia. Which of the following will not give a test for chloride ions with silver nitrate at $25 \ ^oC$?

• A
  $CoCl_3 \cdot 5NH_3$
• B
  $CoCl_3 \cdot 6NH_3$
• C
  $CoCl_3 \cdot 3NH_3$
• D
  $CoCl_3 \cdot 4NH_3$