Which amond the following are unsaturated hydrocarbons ?
(i) `H_(3)C-CH_(2)-CH_(2)-CH_(3)`
(ii) `H_(3)C-C-=C-CH_(3)`
(iii) `H_(3)C-underset(CH_(3))underset(|" ")(CH)-CH_(3)`
(iv) `H_(3)C-underset(CH_(3))underset(|)C=CH_(2)`
A. (i) and (iii)
B. (ii) and (iii)
C. (ii) and (iv)
D. (iii) and (iv)