Alrighty, so, in order to see if A is the correct answer replace the word "was" with "is." This gives us:
The park is large, and we walked for hours.
Because this sentence makes sense, "was" is not an action verb.
Answer C.) is not an action verb it is a pronoun
Answer D.) The word "large" is an adjective.
Therefore the right answer is B.) Walked.
Hope this helped!
