Pansies - student project

These were tougher than I thought. I use white Nights Watercolours and other than Carmine and Hansa Yellow none of the colours used in this tutorial are in the set. So made do with whatever I had. However I was confused about the warm brown. I have Burnt Umber, Burnt Sienna, Umber, Mars Brown in my set. Which of these would be a warm colour? Any advice?

Thank you