Final answer:
The lowest possible value of the Shannon index is 0, which indicates low species diversity. The Shannon index ranges from 0, which implies no diversity, to higher numbers signifying greater diversity.
Step-by-step explanation:
The lowest possible value of the Shannon index is 0. Low values indicate low species diversity. Therefore, the correct answer is B. 0; low. The Shannon index is a measure of species diversity in a community. Values of the index range from 0 to higher numbers, with 0 indicating that there is only one species present, meaning no diversity, and higher values indicating a more diverse community with a greater number of different species.