M365 A5 - How to purchase Windows Server CALs for Students on a EES?

Hi All 

Just checking the cheapest way to cover Students for using on-premise Windows Server? MS have removed this from the Student Use Benefit (SUB) under M365 A5! 

1) Can i use the Student Option?

2) Can i use the External Connector License?

3) Or do i need to purchase WS Cal for each Student?

Thanks