The right option is; A. Iron
Deficiency of iron will most likely impair a child’s growth, mood, attention span, focus, and ability to learn.
Iron is a nutrient that is important to the growth and development of children. Iron functions by transporting oxygen from the lungs to the rest of the body and it also assist muscles to store and use oxygen. Deficiency of iron is when there is too little iron in the body. This condition can affect a child's growth and development and hinder learning abilities including reduced attention span or focus, difficulty understanding new things and stunted growth.