i. autotrophs

ii. heterotrophs

iii. saprotrophs

iv. chemo-autotrophs.

Choose the correct answer:

(a) i and iii, (b) i and iv (c) ii and iii, (d) i and ii

Correct option – ( c )

Explanation – decomposers are those which feed on dead and decaying matter . Autotrophs ans saprotrophs are considered as decomposers , specifically saprotrophs as they decompose organic residues .

Hence correct answer is – heterotrophs and saprotrophs