This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Microbiology
A 5yr old boy presents with sore throat for the last two days On examination he has a greyish white pseudomembrane around his tonsils Diphtheria is suspected His brother has recieved last booster 22 months back What prophylactic measure should be adopted for the brother 
Select and explain. 
A. Prophylaxis with oral erythromycin, B. Nothing is required, C. Prophylaxis with erythromyci and diphtheria antitoxin, D. Immunize with booster of diphtheria toxoid
B: Nothing is required
Answer: B: Nothing is required 
Explanation: National immunization schedule the 3 yr old sibling would have recieved a booster b w 16 24 months of age Nothing needs to be given for diphtheriaprophylaxis if booster has been relieved in last 2yrs REF : BAVEJA MICROBIOLOGY