Arrange the following oxides in decreasing order of oxidation state of the metal ion.
$ (A)\text{Cu}_2\text{O} $
$ (B)\text{CrO}_3 $
$ (C)\text{Mn}_2\text{O}_7 $
$ (D)\text{V}_2\text{O}_5 $
Choose the correct answer from the options given below:

(C), (B), (D), (A)

The correct answer is Option (4) → (C), (B), (D), (A)

Decreasing order (highest to lowest oxidation state):

$\text{Mn}_2\text{O}_7(+7)  >\text{CrO}_3(+6)  >\text{V}_2\text{O}_5(+5)  >\text{Cu}_2\text{O}(+1)$