Macronutrients are required approximately in:
1000 mg/kg dry matter (C) is correct here. This is core MINERAL Transport: once you know the definition or pathway step, 1000 mg/kg dry matter is the clear fit. The wrong ones are A) 100 mg/kg dry matter; B) 10 mg/kg dry matter; D) 1 mg/kg dry matter. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.
Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.