Match the following columns:

Column I (Fertilisers)	Column II (N- content %)
a. Sodium nitrate	1. 13
b. Calcium nitrate	2. 16
c. Potassium nitrate	3. 15
d. Urea	4. 46

Sodium nitrate supplies water supplying a water-soluble form of nitrogen without altering the pH of the soil. It contains 16% of nitrogen.
Calcium nitrate fertilizer is a water-soluble chemical solution that provides plants with supplemental calcium and nitrogen. Its nitrogen content is about 15%.
Potassium nitrate fertilizer is a water-soluble fertilizer with high potassium and nitrogen content along with an optimal amount of sodium, its nitrogen content is 13%.
Urea is the most important nitrogenous fertilizer and is widely used also because of its high Nitrogen content which is about 46%.