The 5G version of the Pixel 4a launched in just one color: black. Unless, of course, you went with the Verizon-exclusive white option instead. However, Google has now announced it is releasing unlocked SKUs of device in both colors from January 28, 2021.
https://www.notebookcheck.net/Google-s-Clearly-White-color-option-is-coming-to-the-non-Verizon-Pixel-4a-5G.514086.0.html