I am currently studying for RHCSA and wish to practice on a system (vm) that is as near as possible to RHEL 7.  I know about the free development version but as per Appendix 1 (Exhibit 1.C), my intended use does not qualify me for the free copy.I use Ubuntu for personal purposes and am unfamiliar with the subtle differences in the RHEL-like OSs.  I am aware of CentOS, Fedora, Scientific Linux, and Oracle Linux, but my question is strictly for the purposes of practicing for the RHCSA exam - which one is the best match for RHEL 7 when considering the following tasks?A Red Hat Certified System Administrator (RHCSA) is able to perform the following tasks:Understand and use essential tools for handling files, directories, command-line environments, and documentationOperate running systems, including booting into different run levels, identifying processes, starting and stopping virtual machines, and controlling servicesConfigure local storage using partitions and logical volumesCreate and configure file systems and file system attributes, such as permissions, encryption, access control lists, and network file systemsDeploy, configure, and maintain systems, including software installation, update, and core servicesManage users and groups, including use of a centralized directory for authenticationManage security, including basic firewall and SELinux configurationAnother user asked a similar question back in 2012, but it was about an earlier RHEL version (and a lot can change in that time).
Closest thing to Red Hat Enterprise Linux 7?
rhel;software rec
As mentioned in the previous question, CentOS  is your best choice since it is derived from the sources of Red Hat Enterprise Linux (RHEL).Also as mentioned in their Technical and Release notes, almost all your required tasks are met in CentOS. 