The correct option is C 16
Essential elements needed for growth and development of plants are 16 in number. These are macronutrients as well as micronutrients. For example, C, H, O, N, P, K, S, Mg, and Ca are macronutrient whereas Fe, B, Mn, Cu, Zn, Mo, and Cl are micronutrients. Thus, the correct answer is option C.