Which of the following is a non-metalic nutrient?

Answer: Option C

Boron is a non-metalic nutrient.
Boron is a non-metallic element and a micronutrient to plants required in small quantities.
Boron plays a key role in a diverse range of plant functions including cell wall formation and stability, maintenance of structural and functional integrity of biological membranes, movement of sugar or energy into growing parts of plants, and pollination and seed set.