The correct option is A Amazon
The diversity of an ecosystem is decided on two factors. Species richness and species evenness. When comparing two ecosystem, both factors are taken into account. However, the species evenness is a deciding factor only when the two ecosystems are equally rich in the number of species. In the case of Amazon forest vs. Western Ghat, the difference in the species richness is far too great to take species evenness into account. Therefore the Amazon forest would be considered to be a much more diverse ecosystem as compared to Western Ghats.