a) Panting and throwing his head from side to side, the dog ran carefree through the grassy field.
Explanation:
The precise language in writing uses precise nouns and vivid verbs to create a specific picture in the readers' mind, it also avoids wordiness. The correct option, in this case, would be a) because is describing the movements of the dog using vivid verbs, the attitude of the dong, and space where the dog is developing its actions.
This is what subject-verb agreement is: <em>I walk</em> versus <em>He walks</em>
When you put something between the subject (I/he) and the verb (walk(s)), the verb does not change. <em> </em><em>I slowly walk. </em><em>He quickly walks.</em>