Refer to the given flow chart showing flow of energy in a food chain.
Select the correct statement regarding P, Q, R and S.
(i) S helps in cleaning of environment as well as recycling of nutrients.
(ii) The role of Q comes when plants and animals die.
(iii) P operate at all levels of food chain.
(iv) R eats other animals and get its food indirectly from P.
A (i) and (iv) only
B (i), (iii) and (iv) only
C (iii) and (iv) only
D (i), (ii), (iii) and (iv)