Copy of Source System = This type of system is a replica of the production system that is in the list which includes everything (i.e master data and all the transaction data) from the existing production system.
Copy of Source System (Copy Solution Profile) = This type of system is the same replica of the existing production system, but provides an option to copy a different solution profile if there is any existing.
Initial System = This type of system is a fresh system without any data in it.
Initial System (Copy Solution Profile) = This type of system is a fresh system again but you again have a choice of choosing a solution profile;
KBA , SRD-FIN-FA , Fixed Assets , How To