Task: Question Answering
Input (English): Question: Patients undergoing gastric surgery require vitamin B12 replacement therapy for: 
 Options:  <1> CLH deficiency - which hinders the absorption of nutrients. <2> Excessive loss of this vitamin in the stool. <3> Low intake of food as a result of anorexia. <4> Deficiency in its absorption due to lack of intrinsic factor. <5> Excessive loss of this vitamin in the urine.
Output (English): 4