How Does Splunk Determine Which Fields to Extract from Data

Multiple Choice

How does Splunk determine which fields to extract from data?

A) Splunk only extracts the most interesting data from the last 24 hours.
B) Splunk only extracts fields users have manually specified in their data.
C) Splunk automatically extracts any fields that generate interesting visualizations.
D) Splunk automatically discovers many fields based on sourcetype and key/value pairs found in the data.