$N_2$ is a stable molecule but $N_4$ molecule is unknown. $P_4$ is much more stable than molecular $P_2.$  Which is the best explanation for this difference

$N_2$  has valence electrons only in bonding and non bonding orbitals, while $P_2$ has some valence electrons in antibonding orbtials.

The greater electronegativity of N compared to P stabilizes the molecules with lower molar masses

The greater size of P compared to N result in decreased overlap in $Pi$ bonds

The preference of $P$ to adopt smaller bond angles than $N$ favours formation of tetrahedral $P_4$ molecules