Which of the following processor occur in the indexing pipeline?

Which of the following processor occur in the indexing pipeline?

A. tcp out, syslog out
B. Regex replacement, annotator
C. Aggregator

D. UTF-8, linebreaker, header

Reference: https://docs.splunk.com/Documentation/Splunk/8.1.0/Indexer/Howindexingworks#Event_processing_and_the_data_pipeline