According to I.C.A.O. all markings on the runways are painted white and on taxiways A. Black B. Red C. Yellow D. Green

The correct answer is: C. Yellow

According to the International Civil Aviation Organization (ICAO), all markings on the runways are painted white, and all markings on taxiways are painted yellow.

• White markings on runways are used to indicate the centerline, edge lines, touchdown zone markings, and other important information for pilots.
• Yellow markings on taxiways are used to indicate the centerline, edge lines, holding position markings, and other important information for pilots.

It is important to note that these are just the standard colors used by ICAO. Individual countries may have their own regulations regarding the colors of runway and taxiway markings.