The best experimental setup to investigate the connection between kinetic energy and temperature would be:
"placing one drop of food coloring in a cup with 50 mL of water at 10ºC; placing one drop of food coloring in a second cup with 50 mL of water at 40ºC."
This setup allows for the comparison of the diffusion of food coloring in water at two different temperatures (10ºC and 40ºC), which directly relates to the effect of temperature on the kinetic energy of particles in the solution. At a higher temperature, the increased kinetic energy of the water molecules will generally lead to faster diffusion of the food coloring.