Answer:
This is an example of e. intentional introduction species
Step-by-step explanation:
The bullfrog tadpoles mentioned in the question "are dumped into the lake or river". This illustrates an introduction of a species into a new habitat.
The concept of introduction of species illustrates how by human activity, species arrive at an environment that is not their original habitat.
This is what the question is talking about and hence, that is the correct answer.