Which of the following species are isoelectronic: , C6H6, CO, CH4, N2, B3N3H6? (The term i...

Which of the following species are isoelectronic: , C6H6, CO, CH4, N2, B3N3H6? (The term isoelectronic means the same thing in the context of molecules and polyatomic ions as it does with regard to atoms and monatomic ions: isoelectronic species have the same number and arrangement of electrons.)