Decomposers like fungi and bacteria are
(i) Autotrophs
(ii) Heterotrophs
(iii) Saprotrophs
(iv) Chemo-autotrophs
Decomposers
Decomposers depend on dead and decayed organisms for nutrition. Thus they are heterotrophs as they can't prepare their own food and are saprotrophs as they feed on dead and decaying organisms.
Final answer
(C) ii and iii