In a multi-tiered Splunk architecture, index-time processing, known as parsing, occurs on the first full Splunk Enterprise instance that receives the data. Universal Forwarders (UFs) do not parse data; they only forward it. In the provided diagram, data flows from UFs to Heavy Forwarders (HFs) and then to Indexers. Both HFs and Indexers are full Splunk instances capable of parsing. The parsing configurations (props.conf, transforms.conf) must be placed on the tier designated to perform this task. This could be the HF tier to offload work from the indexers, or it could be the indexer tier itself. Therefore, the configurations must be installed on all instances performing the parsing role.

A. All universal forwarders: Universal forwarders are designed to be lightweight and do not have the parsing pipeline; they cannot process these configurations.

B. Only the indexers: This is incorrect as parsing can be, and often is, configured to occur on an intermediate heavy forwarder tier.

C. All heavy forwarders: This is incorrect because the heavy forwarders could be configured solely for data routing, deferring all parsing to the indexers.

1. Splunk Enterprise Documentation, Getting Data In Manual: In the section "Configuration file locations for this manual," it states, "For index-time configurations that you make in props.conf, transforms.conf, and fields.conf, you must place the files on the Splunk Enterprise instance that performs the parsing. This is usually the indexer, but can be a heavy forwarder if you use one to parse data before it reaches the indexer." This confirms that either HFs or indexers can be the "parsing instance."

2. Splunk Enterprise Documentation, Forwarding Data Manual: The "Compare forwarder types" table explicitly lists that Universal Forwarders do not perform parsing, while Heavy Forwarders do. This supports why option A is incorrect and why HFs (in options C and D) are a potential location for parsing configurations.

3. Splunk Enterprise Documentation, Managing Indexers and Clusters of Indexers Manual: The chapter on "How indexing works" describes the data pipeline, which includes the parsing phase. This entire pipeline is executed on indexers or, in a tiered architecture, can be executed on heavy forwarders before the data reaches the indexers. This reinforces that the location of parsing is a design choice between HFs and indexers.