One mole of which octahedral complex of cobalt will give 2 moles of AgCl as precipitate when reacts with excess of silver nitrate solution?
a) ( [Co(NH₃)₆]³⁺ )
b) ( [Co(NH₃)₅Cl]²⁺ )
c) ( [Co(NH₃)₄Cl₂]⁺ )
d) ( [Co(NH₃)₄Cl₂]Cl )