You create 4 forms FormA, FormB, FormC and FormD. You want to allow users to open FormA, FormB and FormC at the same time within FormD. Which properties do you need to set?
IsMdiChild on Forms A,B and C; and IsMdiParent on FormD.
MdiParent on Forms A,B and C; and IsMdiContainer on FormD.
IsMdiChild on Forms A,B and C; and IsMdiContainer on FormD.
MdiParent on Forms A,B and C; and IsMdiParent on FormD.