Are Starbucks coffee beans arabica or Robusta?

I'm curious to know, could you clarify for me if the coffee beans used by Starbucks are of the arabica or the robusta variety? It's important to me as a coffee lover to understand the nuances in taste and quality that come with different bean types. Could you provide some insight into the choice Starbucks makes in selecting their coffee beans and the reasons behind it? I'm genuinely interested in learning more about this aspect of their coffee sourcing and production process.