The ecological efficiency in a food chain is 10%. A pollutant (X) is transferred from one trophic level to the next with an efficiency of 30%. The concentration of X on trophic level 2 is 12 ppm. What is the concentration of X on trophic level 1?
A. 4 ppm
B. 12 ppm
C. 40 ppm
D. 120 ppm