This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral cavity, Subject name: Surgery
Which of the following about tobacco and oral cancer are true? i. MC histological type - adenocarcinoma ii. Dose-response relationship iii. Synergistic interaction with alcohol iv. Associated with mutations in p53 gene. No association with smokeless tobacco 
Select and explain. 
A. i, ii, iii, iv, B. ii, iii, iv, C. ii, iii, D. i, iii, iv,
B: ii, iii, iv
Answer: B: ii, iii, iv 
Explanation: Risk Factors for CA Oral Cavity- Tobacco- Alcohol- Betelnut/ Areca nut- Pan Masala- Sharp Jagged tooth- Plummer Vinson syndrome- Ill-fitting denture- Syphilitic glossitis- HPV infections- EBV- Poor nutrition Impoant points of carcinoma of oral cavity:- MC mutation: In CA oral cavity - P53- MC site of CA Oral cavity - Tongue > lip- MC histological type - SCC- MC type of cancer in India - CA oral cavity (Buccal Mucosa > Anterior Tongue> LowerAlveolus)- MC pattern of spread - local extension and regional lymphatic spread- MC site of LN metastasis - lungs- MC lymph node metastasis - CA Tongue- Least common lymph node metastasis - CA lip (CA Hard Palate)- B/L lymphatic spread* lower lip* Supraglottis* Soft Palate- IOC for Dx - Edge Biopsy (Not from centre to avoid taking sample from necrotic areas)- IOC for staging of Head and Neck Malignancies including CA Oral Cavity - MRI- MC flap used for Head & Neck reconstruction - PMMC flap (Pectoralis major myocutaneousflap) - Based on Pectoral branch of Thoraco-Acromial vesselsSkin andvermillion