For humans, which colors are visible on the spectrum?
O orange, yellow, green, blue, black, and white
O white, orange, yellow, green, purple, and black
O red, green, and blue
O red, orange, yellow, green blue, indigo, and violet
O orange, yellow, green, blue, black, and white
O white, orange, yellow, green, purple, and black
O red, green, and blue
O red, orange, yellow, green blue, indigo, and violet