A/B/n Testing: All at Once or In Succession?

If I want to A/B test a button color, but for 5 colors, how do I do it?

Do I equally split traffic to all 5 button colors for 5 weeks

Or… do I run split traffic between red button vs blue button the first week, then after finding that red works better, run the red button vs yellow button the following week, and so on?

Both options seem like they would work, but I'm not sure which to choose.