HPQC/HPALM to SolMan

Please let me know what is the difference between the below components?

1. HP ALM integration with SolMan
2. SAP Quality Center by HP integration with SolMan
3. Charm integration with HPQC?
4. Incident management integration with HPQC?

And also let  me know if there area HP tools can integrate with  SolMan?