The correct option is C Sodium
Based on the quantitative requirements of mineral elements by plants, nutrient elements have been divided into 2 broad categories: Macro and micronutrients.
Macronutrients: C, O, H, Ca, Mg, N, P, S, K
Micronutrient: Mn, Fe, Zn, Cu, Ni, Mo, B, Cl.
Along with these elements, there are few beneficial elements like silicon, sodium, selenium & cobalt. They are not required by all plants but can promote plant growth and may be essential for particular taxa. Higher plants tend to require them.