The correct option is B (a)-(ii), (b)-(iii),(c)-(i)
Rhizobium is a soil bacteria that fixes nitrogen once they found a base inside root nodules of legumes. In other terms, they can be defined as legume root-nodule bacteria.
Microorganisms in forest feed upon the dead plant and animal tissues and convert them into a dark coloured substance called humus. The presence of humus ensures that soil become more porous and allows water and air to penetrate deep underground. Moss is a small flowerless plant that grows on the surface of rocks and influence the formation of soil.