Out of the following oxides, the amphoteric oxide is:

73 The least reactive metal among the following is: 74 An element X reacts with hydrogen, when heated, to form a covalent hydride H₂X. If H₂X has a smell of rotten eggs, the element X is likely to be: 76 The metals which can produce amphoteric oxides are: 77 An element X forms two oxides XO and XO₂. The oxide XO is neutral but XO₂ is acidic in nature. The element X is most likely to be :