Which one of the following stage can be assessed by using a following said empirical equation?
$$A = \frac{{{\text{Economic production}}}}{{{\text{Biomass production}}}}$$

A. Neem B. Eucalyptus C. Cinnamon D. Cinchona

A. Xanthomonas compestris B. Pseudomonas solanacearum C. Puccinia graminis tritici D. Albugo candida

A. a-2, b-1, c-4, d-3 B. a-1, b-4, c-3, d-2 C. a-4, b-3, c-2, d-1 D. a-3, b-2, c-1, d-4

A. Wheat B. Sunhemp C. Cotton D. Rice