Which one of the following cannot form an amphoteric oxide?

Identify the incorrect statements about group $15$ elements :
$A$. Dinitrogen is a diatomic gas which acts like an inert gas at room temperature.
$B$. The common oxidation states of these elements are $-3, +3$ and $+5$.
$C$. Nitrogen has unique ability to form $p\pi-p\pi$ multiple bonds.
$D$. The stability of $+5$ oxidation states increases down the group.
$E$. Nitrogen shows a maximum covalency of $6$.
Choose the correct answer from the options given below.

$A$ non-metal $M$ forms $MCl_3$,$M_2O_5$ and $Mg_3M_2$ but does not form $MI_5$. Then the incorrect statement regarding non-metal $M$ is:

What happens when $H_{3}PO_{3}$ is heated?

Which of the following oxyacids contains both $P-H$ and $P-P$ bonds simultaneously?

The incorrect statement about $PH_3$ is: