The common features, among the species CN-, CO, and NO+ are:

Explanation

Each of these have same number of electrons;Number of electrons in CO = 6+8 = 14Number of electrons in CN- = 6+7+1 = 14Number of electrons in NO+ = 7+8-1 = 14 The species having same number of electrons are called iso-electronic. Iso-electronic species have same bond order.Bond order is number of chemical bonds present between a pair of atoms. There are 3 chemical bonds between C and O in CO, C and N in CN- and N and O in NO+ so all of these have same bond order of 3.Hence, all the given species are iso- electronic and have same bond order. So, option A is correct.