Identify the correct statements from the following
i) oxygen shows -2,-1,+1,+2 oxidation states
ii) the thermal stability of $H_{2}O,H_{2}Se,H_{2}S$  follows the order $H_{2}O<H_{2}S<H_{2}Se$ 
iii) the reducing nature of $H_{2}Se,H_{2}S,H_{2}Te$  follows the order $H_{2}S<H_{2}Se<H_{2}Te$