Arrange the following compounds in the increasing order of their densities.
(i) (a) < (b) < (c) < (d)
(ii) (a) < (c) < (d) < (b)
(iii) (d) < (c) < (b) < (a)
(iv) (b) < (d) < (c) < (a)
(a) Density increases with increase in molecular mass. The order of molecular masses is (a) < (b) < (c) < (d)
Hence option (i) (a) < (b) < (c) < (d) is correct.