Optical vs coax vs spdif

The local classical radio station 101.1 FM DALLAS. Is giving away their entire CD collection at MY restaurant!!! Awesome 😎, but I haven’t used a CD player in my setup in years. I got on eBay and scored a Marantz PMD321 for like $50 bucks including shipping. 

i want to use my dac (simaudio Moon 280d) but I don’t know what kind of digital connection would work best. 

Should i I use optical, coax, or spdif... 

thanks