A 30-year-old woman presents with rapid swelling beneath her jaw that suddenly appears while she is eating. The swelling is mildly painful but is not hot or red. You suspect Wharton salivary duct stones and proceed to palpate
a. bilaterally along the buccal mucosa.
b. under the tongue, along each side of the frenulum.
c. beside the gingivae near each molar.
d. along the roof of the mouth.