The coordination number of central metal atom in a complex is determined by

• Correct answer
  A

  the number of ligands around a metal ion bonded by sigma bonds
• B

  the number of only anionic ligands bonded to the metal ion
• C

  the number of ligands around a metal ion bonded by sigma and pi- bonds both
• D

  the number of ligands around a metal ion bonded by pi-bonds

Hence, the correct answer is option: 'A'.