How Are Markedly Negative Results of a Multi-Site Interventional Nursing

How are markedly negative results of a multi-site interventional nursing study with a huge sample and stringent level of significance helpful?

A) They rule out the usefulness of the intervention for all clients.
B) They provide evidence that may change clinical practice, if the intervention is currently being applied in practice to all healthcare clients.
C) They contribute to the total body of nursing knowledge.
D) They may indicate different directions for theoretical ideas.
E) They establish the fact that the intervention is not universally effective with all clients.
F) They allow only cautious generalization.