Which one is a C4 plant?
In C3 plants first product is 3 carbon compound called phosphoglyceric acid (PGA) while in C4 plants, the first product is 4 carbon compound called the oxaloacetic acid (OAA).
A. Potato- C3 plant.
B. Mustard- C3 plant.
C. Onion- C4 plant.
D. Wheat- C3 plant.
Hence, the correct answer is 'Onion'.