Step 1: Frame the answer by the WHO age/weight tiers for vitamin A. Infants under 6 months get $50{,}000$ IU, those 6-12 months or under 8 kg get $100{,}000$ IU, and children over 1 year up to 6 years get $200{,}000$ IU.
Step 2: A 2 year old at 12 kg clearly falls in the over-1-year, over-8-kg category, so the prescribed oral dose is $200{,}000$ IU, equal to 2 lakh IU.
Step 3: The schedule repeats the dose the following day and again after 2-4 weeks, confirming the high oral mega-dose choice. \[\boxed{2\ \text{lakh I.U.}}\]