Answer:
The hypothesis that will best demonstrate an economic benefit to the ranchers will be "Pastures with the highest diversity of plant species will have the highest net primary productivity."
Step-by-step explanation:
This hypotheses would best demonstrate an economic benefit because it clearly states that when plant species are diverse, this will provide the highest net productivity to the ranchers. Hence if the aim of the student is to determine if increasing species diversity of edible plant would lead to great economic benefits, then this suits for the hypotheses.