Question De Jour

I have to choose T-Shirt colours out for Volunteers, Supervisors and Supervisor Coordinators for an upcoming event. Every year is a conundrum, trying to pick colours that are more noticable in a crowd that's not so hideous that I have twenty Supervisors muttering.

The choices are Aquamarine, Red, Apricot and Lemon.

What's your favourite T-Shirt colour for keeping cool and hiding dirt?

Please help!