Which of the following metal oxides is not amphoteric?

When $SO_{2}$ is passed through acidified $K_{2}Cr_{2}O_{7}$ solution:

Given below are two statements:
Assertion $(A)$: All $Cu$ $(II)$ halides are known except the iodide.
Reason $(R)$: $Cu^{2+}$ oxidizes $I^{-}$ to $I_2$.
The correct answer is:

Which one of the following oxides is ionic?

Arrange the oxides $CrO$,$CrO_3$,and $Cr_2O_3$ in the decreasing order of acidic strength.

Which of the following is the correct order of negative values of $E^o\,M^{2+} | M$ for the elements $Cr, Mn, Fe,$ and $Co$?