Graphics images are stored as two-dimensional arrays of pixels. Many use 24-bits of memory space for each pixel. This is further divided up into three 8-bit sequences that store the RGB (Red, Green, Blue) values of each pixel. If 24-bits are used for one pixel and this pixel's color is determined by three Red, Green, Blue value, each using 8-bits, how many different color combination exist for a pixel?
(A) 512
(B) 4,096
(C) 262,144
(D) 16,777,216