CAN is a/an

Answer: Option C

Can is a nitrate fertilizer and ammonium fertilizer.
Calcium ammonium nitrate or CAN, also known as nitro-limestone or nitrochalk, is a widely used inorganic fertilizer, accounting for 4% of all nitrogen fertilizers.
CAN is a nitrogen fertilizer that contains equal parts of fast acting nitrate-nitrogen and longer lasting ammonium-nitrogen. This ensures a more continuous nitrogen supply to the crop and thus better efficiency of use, and also makes it suitable for unseasonal application during summer or winter.