This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Anatomy
Commonest type of carcinoma with gallstones is 
Select and explain. 
A. Adenocarcinoma, B. Anaplastic carcinoma, C. Squamous cell carcinoma, D. Transitional cell carcinoma
A: Adenocarcinoma
Answer: A: Adenocarcinoma 
Explanation: Histological types of gallbladder carcinoma Diffuse infiltrative : MC type Nodular or mass forming Papillary : Exhibits polypoid or cauliflower appearance and have best prognosis Adenocarcinoma : MC histological subtype of CA GB associated with gallstones Ref: Sabiston 20th edition Pgno : 1512-1514