The Brazil Nut Tree, Bertholletia Excels, Is Native to Tropical

The Brazil nut tree, Bertholletia excels, is native to tropical rain forests of South America. Scientists have discovered that the pale yellow flowers of Brazil nut trees cannot fertilize themselves and admit only female orchid bees as pollinators.
Entrepreneurs attempted, but failed, to harvest nuts from plantations grown in Southeast Asia. Attempts to grow Brazil nut trees in South American plantations also failed. In both cases, the trees grew vigorously, produced healthy flowers in profusion, but set no fruit. Which of the following statements best explains the failure to cultivate Brazil nut trees in these other locations?

A) The trees exhibited poor sporophyte viability.
B) The trees failed to produce fertile ovules.
C) The trees failed to produce pollen.
D) The flowers were not pollinated due to the absence of female orchid bees.