Hello, girls, My son has a deficiency in vitamin D and iron. The pedia…

Hello, girls, My son has a deficiency in vitamin D and iron. The pediatrician prescribed Aquadetrim and Ferrovit C. So which vitamin D is better: Aquadetrim, Detrimax, or Vigantol?! And how should I give Ferrovit so that it doesn't blacken the teeth? Will the blackness go away after the treatment?