Match column I with column II and select the correct answer from the given codes.
| Column I | Column II | ||
|---|---|---|---|
| A, | Methanogens | (i) | BOD |
| B. | Fermentors | (ii) | Methane rich fuel gas |
| C. | Organic waste in water | (iii) | Production of methane |
| D. | Biogas | (iv) | Large vessels for growing microbes |