The correct answer is
A) semanage port -a -t ssh_port_t -p tcp 2222
This command will allow the SSH server to bind to port 2222 by adding it to the SELinux policy. The semanage command is a utility for managing SELinux policies. The port subcommand is used to manage network port definitions. The -a option is used to add a new record, the -t option is used to specify the SELinux type, the -p option is used to specify the protocol, and the tcp 2222 argument is used to specify the port number. The ssh_port_t type is the default type for SSH ports in SELinux.
The other options are incorrect because:
B) chcon system_u:object_r:ssh_home_t /etc/ssh/*
This command will change the SELinux context of all files under /etc/ssh/ to system_u:object_r:ssh_home_t, which is not correct. The ssh_home_t type is used for user home directories that are accessed by SSH, not for SSH configuration files. The correct type for SSH configuration files is sshd_config_t.
C) iptables -A INPUT -p tcp --dport 2222 -j ACCEPT
This command will add a rule to the iptables firewall to accept incoming TCP connections on port 2222. However, this is not enough to fix the issue, as SELinux will still block the SSH server from binding to that port. Moreover, iptables may not be the default firewall service on some Linux distributions, such as Fedora or CentOS, which use firewalld instead.
D) firewall-cmd --zone=public --add-port=2222/tcp
This command will add a rule to the firewalld firewall to allow incoming TCP connections on port 2222 in the public zone. However, this is not enough to fix the issue, as SELinux will still block the SSH server from binding to that port. Moreover, firewalld may not be installed or enabled on some Linux distributions, such as Ubuntu or Debian, which use iptables instead.
Reference:
How to configure SSH to use a non-standard port with SELinux set to enforcing Change SSH Port on CentOS/RHEL/Fedora With SELinux Enforcing How to change SSH port when SELinux policy is enabled

The reason the firewall rules are not active is that the firewalld service is not enabled. This means that the service will not start automatically at boot time or after a system reload. To enable the firewalld service, the systems administrator needs to use the command sudo systemct1 enable firewalld. This will create a symbolic link from the firewalld service file to the appropriate systemd target, such as multi-user.target. Enabling the service does not start it immediately, so the systems administrator also needs to use the command sudo systemct1 start firewalld or sudo systemct1 reload firewalld to activate the firewall rules.
The other options are not correct reasons for the firewall rules not being active. iptables is not conflicting with firewalld, because firewalld uses iptables as its backend by default. The wrong system target is not activated, because firewalld is independent of the system target and can be enabled for any target. FIREWALL_ARGS has no value assigned, but this is not a problem, because FIREWALL_ARGS is an optional environment variable that can be used to pass additional arguments to the firewalld daemon, such as --debug or --nofork. If FIREWALL_ARGS is empty or not defined, firewalld will use its default arguments. Reference: firewalld.service(8) - Linux manual page; firewall-cmd(1) - Linux manual page; systemct1(1) - Linux manual page

Some good security practices when hardening a Linux server are:
Removing unnecessary packages (B) to reduce the attack surface and eliminate potential vulnerabilities Disabling the SSH root login possibility (E) to prevent unauthorized access and brute-force attacks on the root account Reference:
[CompTIA Linux+ Study Guide], Chapter 9: Securing Linux, Section: Hardening Linux
[How to Harden Your Linux Server]