The correct answer is D. Inferior labial artery.
The photograph demonstrates a wedge resection which is used to repair defects of the lower lip. During this repair, the inferior labial artery is likely to be severed since it courses superficially between the mucosa and the underlying muscle.
The angular artery, mental nerve, buccal nerve, and marginal mandibular nerve are unlikely to be severed during a wedge resection of the lower lip.
References: Sebben JE. Wedge resection of the lip: minimizing problems. J Dermatol Surg Oncol. 1985 Jan;11(1):60-4. PubMed Link: https://www.ncbi.nlm.nih.gov/pubmed/3965521.