In: Chemistry
1. the electronegativity order is Se>As>Ge. so the most polar bond is Se-Ge and the other answers have been marked in the question itself and could be explained from the electronegativity order explained.
2. electronegativity order is Br>As>Ge. so in Ge-As, Ge as the charge while As has charge. In Ge-Br, Ge has the charge while Br has charge. In Br-As, As has the charge while Br has charge. From this it can be concluded that the most polar bond is Ge-Br.
3. order of electronegativity for the given elements is O>Se>Te. so in Te-O, O has charge while Te has charge. In Te-Se, Te has charge while Se has charge. In O-Se, O has charge while Se has charge. So the most polar bond among the given compounds is Te-O.