During inferior alveolar nerve block, the needle of LA syringe is penetrated into  parotid gland. Which of the following structure is most likely to be penetrated?
Inferior alveolar nerve block (generally called inferior alveolar block or 1A block): 

It is the most common nerve block performed in dentistry to carry out dental procedures on the mandibular teeth.
The anesthetic agent is injected slightly superior to the entry of inferior alveolar nerve into the mandibular foramen being overhung by the lingula.
While performing inferior alveolar nerve block, if needle is inserted too far posteriorly, it may enter the parotid gland and prick the external carotid artery

Ref: Textbook of Anatomy, Vishram singh, pg no:141
Lingual nerve
Lingual artery
ICA
ECA