Question

what relationship do they have? a deed "to A & B, as the Joint tenants with the right of survivorship, and to C & D, as the joint tenants wity the right of survivorship" is the relationship between "A &B" and "C &D" also joint tenancy?? or tenanycy in common???? if these four people had joint tenancy among them, will this joint tency become tenancy in common after one of them die?