Ans. B: 6 monthsNational programme for prevention of nutritional blindness focuses onPromoting consumption of vitamin A rich foods by pregnant and lactating women and by children under 5 years of age.Administration of massive doses of vitamin A up to 5 years. First dose of 100,000 IU with measles vaccination at 9 months and subsequent doses of 200,000 IU each, every 6 months up to the age of 5 years should be given.