B

Unexplained numbness in the distribution of the mental nerve (“numb-chin syndrome”) is most commonly linked to metastatic involvement of the mandible or skull base and is considered an ominous sign of occult or recurrent malignancy, whereas infection, dental manipulation, or CNS lesions are far less frequent causes in this setting [Balamurugan, 2017, PMID 28041759; Colella, 2009, PMID 19359984].