Step 1: The task.
We must match three traits to the right plants in the correct order. The traits are solitary inflorescence, self pollination, and fasciculated roots.
Step 2: First trait, solitary inflorescence.
A solitary inflorescence means flowers borne singly. This fits Datura, which is plant B. So the first plant is B.
Step 3: Second trait, self pollination.
Self pollination is well known in Pisum, the garden pea, which is plant D. That is why Mendel used it. So the second plant is D.
Step 4: Third trait, fasciculated roots.
Fasciculated roots grow in clusters and are seen in Asparagus, which is plant A. So the third plant is A.
Step 5: Building the order.
Reading the traits in order gives the series B, D, A.
Step 6: Conclusion.
Therefore the correct answer is "B, D and A". \[ \\boxed{\\text{B, D, A}} \]