Mang Kepwing owned a 5 ha of rice field which he planted for commercial purposes. When the crop reaches its vegetative phase he notices some parts of the area show symptoms which as yellowing of leaves. But he doesn’t know exactly the main reason why that particular problem suddenly arises. He contact some experts who stated that it might be the cause of nutrient deficiency so the expert advise the farmer in that large area he need to examine the soil with sensors in real-time and which can help determine nitrogen deficiency and then the control system estimates the required number of inputs. Based on the statement given, what particular sensor should be applied to solve Mang Kepwing's problem?

A. SSCM

B. UAVs

C. VRT

D. None of the choices

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