During the experiment of heating of ferrous sulphate crystals, four students recorded their observations as observations as:
(i) green colour of crystals changes to brown black colour
(ii) brownish yellow gas is evolved
(iii) blue colour of crystals changes to green colour
(iv) smell of burning sulphur is felt
Which of the above observations are correct?
(A) (i), (ii)
(B) (i), (iv)
(C) (ii), (iii)
(D) (iii), (iv)