The correct options are
A The highly electronegative fluorines on being placed on sulphur atoms can appreciably contract the 3d-orbital to facilitate N(2pn)→S(3dn)π-bonding.
B In S4N4H4, the hydrogens never go on sulphurs while in S4N4F4, fluorines get preferably attached with sulphur atoms.
C If in S4N4H4, hydrogens go to the sulphurs, no π-bonding occurs through the 3d-orbitals of S.
D N−H bond is stronger than the S−H bonds.
All the four statements are correct.
(A) In S4N4H4, the hydrogens never go on sulphurs, they are on N atoms while in S4N4F4, fluorines get preferably attached with sulphur atoms, they do not go with N atoms. Both N and F are highly electronegative and do not form stable bonds easily.
(B) The highly electronegative fluorines on being placed on sulphur atoms can appreciably contract the 3d-orbital of facilitate N(2pn)→S(3dn)π-bonding.
(C) If in S4N4H4 hydrogens go to the sulphurs, no effective π-bonding occurs through the 3d-orbitals of S.
(D) N−H bond is stronger than the S−H bonds because of high electronegativity difference.