According to the Splunk documentation1, to customize a configuration file, you need to create a new file with the same name in a local or app directory. Then, add the specific settings that you want to customize to the local configuration file. Never change or copy the configuration files in the default directory. The files in the default directory must remain intact and in their original location. The Splunk Enterprise upgrade process overwrites the default directory.
To deploy configuration files to deployment clients, you need to use the deployment server. The deployment server is a Splunk Enterprise instance that distributes content and updates to deployment clients2. The deployment server uses a directory called $SPLUNK_HOME/etc/deployment-apps to store the apps and configuration files that it deploys to clients2. To update the configuration files in this directory, you need to edit them manually and then run the command $SPLUNK_HOME/bin/sp1unk reload deploy-server to make the changes take effect2.
Therefore, option A is incorrect because it does not include the reload command. Option B is incorrect because it makes the change on a deployment client instead of the deployment server. Option D is incorrect because it changes the default directory instead of the local directory.
References: 1: How to edit a configuration file - Splunk Documentation 2: Deployment of configuration files - Splunk Community

https://docs.splunk.com/Documentation/Splunk/latest/Admin/Wheretofindtheconfigurationfiles To determine the order of directories for evaluating configuration file precedence, Splunk software considers each file's context. Configuration files operate in either a global context or in the context of the current app and user: Global. Activities like indexing take place in a global context. They are independent of any app or user. For example, configuration files that determine monitoring or indexing behavior occur outside of the app and user context and are global in nature. App/user. Some activities, like searching, take place in an app or user context. The app and user context is vital to search-time processing, where certain knowledge objects or actions might be valid only for specific users in specific apps.

https://docs.splunk.com/Documentation/Splunk/8.0.5/Admin/Inputsconf
[tcp://<remote server>:<port>]
*Configures the input to listen on a specific TCP network port.
*If a <remote server> makes a connection to this instance, the input uses this stanza to configure itself.
*If you do not specify <remote server>, this stanza matches all connections on the specified port.
*Generates events with source set to "tcp:<port>", for example: tcp:514
*If you do not specify a sourcetype, generates events with sourcetype set to "tcp-raw"

In Splunk Enterprise, when knowledge bundles (which include lookup files, configurations, and other knowledge objects) are replicated between search heads and indexers, administrators can control the maximum size of lookup files that are eligible for replication.
The correct parameter to use is excludeReplicatedLookupSize, defined in distsearch.conf. This parameter specifies a maximum file size (in megabytes) beyond which lookup files are excluded from bundle replication. By setting this to 500, any lookup file larger than 500 MB will not be replicated to search peers.
This is especially important for performance optimization and preventing unnecessary network load during search head to indexer communication.
Example configuration (distsearch.conf):
[replicationSettings]
excludeReplicatedLookupSize = 500
Reference (Splunk Documentation):
* distsearch.conf.spec and example # excludeReplicatedLookupSize
* Splunk Enterprise Distributed Search Manual # "Control knowledge bundle replication between search heads and indexers"
* Splunk Admin Manual # "Prevent large lookup files from being replicated"

After an app is downloaded, it resides under $SPLUNK_HOME/etc/apps on the deployment clients. But it resided in the $SPLUNK_HOME/etc/deployment-apps location in the deployment server.