The element with the maximum number of oxidation states among the given options is Mn (Manganese).

Explanation:
Manganese (Mn) is a transition metal that has a wide range of oxidation states due to the availability of different d orbitals for electron transfer. The possible oxidation states of Mn can range from -3 to +7.

Let's analyze the given options and their possible oxidation states:

a) Cr (Chromium): Chromium has a maximum oxidation state of +6. It can also exhibit oxidation states of +3, +2, and -2. Therefore, it does not have as many oxidation states as Mn.

b) Fe (Iron): Iron has a maximum oxidation state of +6. It can also exhibit oxidation states of +3, +2, and -2. Similar to chromium, it does not have as many oxidation states as Mn.

c) Mn (Manganese): Manganese has a maximum oxidation state of +7. It can also exhibit oxidation states of +6, +4, +3, +2, +1, -1, and -3. Therefore, Mn has the highest number of possible oxidation states among the given options.

d) V (Vanadium): Vanadium has a maximum oxidation state of +5. It can also exhibit oxidation states of +4, +3, +2, and -1. Although vanadium has a high number of oxidation states, it is still lower than the possible oxidation states of Mn.

In conclusion, among the given options, Mn shows the maximum number of oxidation states ranging from -3 to +7.