Answer:
Letter B is the best option to complete the sentence:
When Diane takes her beagle for a walk, Santana enjoys sniffing for edible garbage, howling at bicyclists, and lunging at squirrels.
Step-by-step explanation:
This question concerns the use of parallelism in a sentence. Parallelism occurs when we repeat the same grammatical structure in a sentence, which helps with the organization and understanding of that sentence. Parallelism is especially useful when listing items, ideas, or examples.
In the sentence we are analyzing here, three behaviors of Santana are listed. The two behaviors mentioned in the sentence use the structure "verb + ing + object". Therefore, to keep the structure parallel, we must choose the option that uses the same grammatical structure. That would be letter B. howling at bicyclists.