**Core Concept**
The national immunization schedule involves administering Vitamin A supplements to children to prevent vitamin A deficiency and its complications. The total dose of Vitamin A is a critical component of this program, and it is essential to understand the recommended dose to ensure the health and well-being of children.

**Why the Correct Answer is Right**
The World Health Organization (WHO) recommends that children receive a total dose of 100,000 IU of Vitamin A at 9 months of age, followed by a booster dose of 100,000 IU at 12-18 months. The doses are usually administered intramuscularly (IM) or subcutaneously (SC), but not intravenously (IV). However, in some cases, Vitamin A may be given intravenously in severe cases of vitamin A deficiency. The correct total dose of Vitamin A is 17 lac (17,000,000) IU, which is administered intravenously in some cases.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as the total dose of Vitamin A is not 16 lac IU. The dose is significantly higher than this option suggests.
**Option C:** This option is incorrect as the total dose of Vitamin A is not 18 lac IU. This dose is higher than the recommended dose, which could lead to toxicity.
**Option D:** This option is incorrect as the total dose of Vitamin A is not 20 lac IU. This dose is significantly higher than the recommended dose and could lead to toxicity.

**Clinical Pearl / High-Yield Fact**
It is essential to note that Vitamin A toxicity can occur if the recommended dose is exceeded. Symptoms of Vitamin A toxicity include headaches, dizziness, and nausea, which can progress to more severe complications if left untreated.

**✓ Correct Answer: B. 17 Lac IV**