(i) might be true, you can have a scalene triangle with one angle being 60°, (if all the other angles were also 60°) BUT we don’t know the other angles so it is possible that it is not a scalene as well
(ii) must be true, because all angles in a triangle must add up to 180° (120°+60°=180°)
(iii) cannot be true, because in order to be obtuse that means the other angles must both be bigger than 90°, and 91°+ 91° is 182°,but ALL three angles of a triangle must equal 180° together therefore there wouldn’t be any room for the 60°
(iiii) Might be true, 60° plus a right angle (90°) gives you 150°, and the other angle would be 30°, so you can’t tell for sure if it’s a right angle triangle but it is possible that is could be.