**Core Concept**
The treatment of vitamin A deficiency in children involves administering high doses of vitamin A to rapidly correct the deficiency and prevent complications such as night blindness, xerophthalmia, and even death. The World Health Organization (WHO) recommends a specific schedule for vitamin A supplementation in children with vitamin A deficiency.

**Why the Correct Answer is Right**
The correct answer is D. 1 lakh units on day 0, 1 and 14. This schedule is based on the WHO recommendations for vitamin A supplementation in children with vitamin A deficiency. The child should receive 100,000 IU of vitamin A on the day of diagnosis, followed by another dose on the next day, and a third dose 2 weeks later. This schedule helps to rapidly correct the vitamin A deficiency and prevents complications.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the WHO recommends a dose of 100,000 IU, not 200,000 IU. Administering a higher dose can lead to toxicity.
**Option B:** This option is incorrect because it only recommends two doses, whereas the WHO recommends three doses for rapid correction of vitamin A deficiency.
**Option C:** This option is incorrect because it recommends administering the first dose on day 0 and the second dose on day 1, but then skips the third dose on day 14.

**Clinical Pearl / High-Yield Fact**
It is essential to note that vitamin A supplementation should only be administered under the guidance of a healthcare professional, and the child should be monitored for signs of toxicity, such as vomiting, diarrhea, and headache. Additionally, vitamin A supplementation should not be given to children with liver disease, as it can exacerbate the condition.

**✓ Correct Answer: D. 1 lakh units on day 0, 1 and 14**