RRB 2010 Bhubaneswar Question 46: select the macro plant nutrients: I. Phosphorous II. Iron III. Carbon IV. Nitrogen

The primary macro nutrients obtained from the soil are nitrogen, phosphorous and potassium and carbon is a primary macro nutrient that is absorbed from the air. So, I, III and IV.

Thanks.
There seems to be some mistakes in some RRB previous year papers ' answers