In the Microarray Shown in the Textbook, the CDNAs Were

In the microarray shown in the textbook, the cDNAs were labeled with red and green fluorescent tags. Why do some spots on the microarray emit yellow light?

A) Red and green are two of the primary colors, and if both cDNAs hybridize to the spot, the combination of the two will produce yellow light.
B) The yellow light comes from the laser, and a yellow spot indicates that neither cDNA hybridized to that spot on the microarray.
C) The over expression of one cDNA relative to the other will skew the color pattern of the spot on the microarray, resulting in the yellow color.
D) The color choice was an arbitrary decision by the artist and doesn't reflect how the process actually works.
E) Yellow spots are those that contain no DNA probes on the chip.