Complex compounds are molecular compounds which retain their identities even when dissolved in water β Coordination Compounds Chemistry Question
Question
Complex compounds are molecular compounds which retain their identities even when dissolved in water. They do not give all the simple ions in solution but instead furnish complex ions. The complex compounds are often called coordination compounds because certain groups called ligands are attached to the central metal ion by coordinate or dative bonds. Coordination compounds exhibit isomerism, both structural and stereoisomerism. The structure, magnetic property, colour and electrical properties of complexes are explained by various theories.

π‘ Solution & Explanation
Step 1: Identify that CN^-, CO, and NO^+ are 14-electron isoelectronic species (CN^- = 6+7+1 = 14; CO = 6+8 = 14; NO^+ = 7+8-1 = 14). Step 2: According to molecular orbital (MO) theory, any 14-electron diatomic species has a bond order of 3.0 with all electrons paired in the molecular orbitals. Step 3: Consequently, all three species are diamagnetic and possess a bond order of three, matching option (a).