Explanation
The answer to your question is C. services/data/collector. This is the endpoint URI used to collect data in a customer managed Splunk Enterprise environment.According to the Splunk documentation1, "The HTTP Event Collector REST API endpoint is /services/data/collector.You can use this endpoint to send events to HTTP Event Collector on a Splunk Enterprise or Splunk Cloud Platform deployment." You can also use this endpoint to send events to a specific token or index1. For example, you can use thefollowing curl command to send an event with the token 578254cc-05f5-46b5-957b-910d1400341a and the index main:
curl -k https://localhost:8088/services/data/collector -H'Authorization: Splunk
578254cc-05f5-46b5-957b-910d1400341a'-d'{"index":"main","event":"Hello, world!"}'