Ans. is 'a' i.e., Repeat the whole course o Interval between doses of DPT: Current recommendation: Allow an interval of 4 weeks between 3 doses, followed by a booster at age of 11/2 -- 2 years, followed by another booster at 5 -- 6 years 2 month intervals DO NOT offer any advantage over 1 -- month intervals for protection against Diphtheria and Tetanus, and may not enhance Peussis protection Shoer intervals confer protection at an earlier age which may be paicularly impoant in Peussis control In the given question, a 11-month old child has received two doses of DPT and polio, comes for fuher immunization after 5 months of the last dose, Then, repeat the whole course