Which of the following mineral can induce the synthesis of metallothionein?

Metallothioneins are a family of cysteine-rich, low molecular weight proteins localised to golgi apparatus. SH group of these proteins bind to physiological (copper and zinc) and xenobiotic metals (cadmium, mercury, silver, arsenic). Zinc and Cadmium induces the production of metallothionein -This propey is used in Wilson's disease as zinc reduces the intestinal absorption of copper by increasing the level of copper sequestering metallothionein.