Question: Which of the following structures travel through the substance of the parotid gland?
A: The maxillary artery
B: The maxillary artery and retromandibular vein
C: The maxillary artery, retromandibular vein and facial artery
D: The maxillary artery, retromandibular vein, facial artery and buccal branch of the mandibular nerve
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.