Simpson's Index Is One Way to Measure $\alpha$ -Diversity

Simpson's Index is one way to measure $\alpha$ -diversity. It would be closest to 1 for which of the following communities?

A) Organisms in a harsh desert environment.
B) Grasses living on a well-managed wheat farm.
C) Organisms living in Antarctica.
D) Organisms in a northern Australian rain forest.
E) Organisms in grassy woodlands.