Answer
c) have the same number of protons.
Work Step by Step
The mass number of oxygen-16 and oxygen-17 are 16 and 17 respectively.
But, mass number=number of nucleons. This implies that the number of nucleons is different. As both are oxygen nuclei, the atomic number or the number of protons are equal. Since the number of nucleons is different, the neutron number should be different for the two. Therefore, option (c) is the correct answer.