We know that : `NDP_(FC)=COE+OS+MI`
Hence, we need to find `NDP_(FC)` first as data on components of operationg surplus is not given
1. `GVO_(MP)=` Sales + Change in stocks
`=4000+0= Rs 4000` crore
2. `GDP_(MP)=GVO_(MP)-IC`
`=4000-600= Rs 3400` crore
3. `NDP_(FC)=GDP_(MP)-"Dep."-NIT`
`=3400-200-500= Rs 2700` crore
4. `NDP_(FC)=COE+OS+MI`
`2700=800+OS+1400`
`OS=2700-2200= Rs 500` crore
