In order to configure IOC, you require the following:
* A one-year subscription to IOC. Note that FortiAnalyzer does include an evaluation license, but it is restrictive and only meant to give you an idea of how the feature works.
* A web filter services subscription on FortiGate device(s)
* Web filter policies on FortiGate device(s) that send traffic to FortiAnalyzer Compromised Hosts or Indicators of Compromise service (IOC) is a licensed feature.
To view Compromised Hosts, you must turn on the UTM web filter of FortiGate devices and subscribe your FortiAnalyzer unit to FortiGuard to keep its local threat database synchronized with the FortiGuard threat database. See Subscribing FortiAnalyzer to FortiGuard.
Ref : https://docs.fortinet.com/document/fortianalyzer/6.4.0/administration-guide/137635/viewing-compromised-hosts

https://docs.fortinet.com/document/fortianalyzer/6.2.0/administration-guide/651442/fetcher-management

Reference:
FortiAnalyzer_Admin_Guide/3600_FortiView/0200_Using_FortiView/1200_Compromised_hosts_page.htm?
TocPath=FortiView%7CUsing%20FortiView%7C_____6

Option B is correct because you must establish an IPsec tunnel ID and pre-shared key to secure the communication between FortiAnalyzer and FortiGate with IPsec12. The tunnel ID is a unique identifier for each tunnel and the pre-shared key is a secret passphrase that authenticates the peers.
Option D is correct because IPsec is only enabled through the CLI on FortiAnalyzer1. You cannot configure IPsec settings through the GUI on FortiAnalyzer.