How is the variability in oxidation states of transition metals different from that of non-transition metals? Illustrate with an example.

a. Transition metals have fixed oxidation states, unlike non-transition metals.
b. Transition metals exhibit a wider range of oxidation states compared to non-transition metals.
c. Non-transition metals are more reactive in terms of oxidation states.
d. Non-transition metals do not show any variability in oxidation states.