If you must have an Apple-brand drive, get the Apple USB Superdrive and an Apple USB-C to USB adapter. (The USB SuperDrive has a reputation for being picky about power, and so might not work if connected to a third-party dock or hub.)
There are many third-party bus-powered drives, some of which are much cheaper, but some of those tie up two USB ports. (The drive transfers data over one, and sucks power from both.)
I picked up one of these for my Mac.
Other World Computing – 24X OWC Mercury Pro Super-Multi DVD/CD Burner/Reader External Optical Drive with M-DISC Support
This drive has its own power supply, so it doesn't need to be connected directly to your Mac. You can plug it into a USB 3.0 (or better) port on a dock or hub. The included USB-A to USB 3.0 B cable is very short, but since it is not permanently attached to the drive, it is easy to replace it with a longer USB-A to USB 3.0 B or USB-C to USB 3.0 B cable from a place like Amazon.