How does the service link work

If i link my service to f.eks an mongodb cluster with three instances.
How does the link determine which node to link to?

Will it work somewhat as a load balancer?
Or does it simply give an dns result with multiple addresses?

It returns multiple A records in random order with short TTLs, which for some DNS clients works somewhat as a balancer (DNS round robin), and for others not so much.

Thanks for the clarification.
Sounds like it should work well for me, if the .net default dns client sorts the list I believe I can manually randomize it until your suggestion is implemented.