A patient experiences pain and some gingival swelling in the anterior segment of the mandible. The mandibular lateral incisor has a shallow restoration, is tender to percussion and gives a positive response to the electric pulp tester. There is some mobility. The most likely diagnosis is

lateral periodontal abscess.

acute apical abscess.

acute serous pulpitis.

chronic ulcerative pulpitis.

acute suppurative pulpitis.