In Azure cognitive search, an indexer for text content simplifies the complex process of loading an index by providing a mechanism for connecting to and reading text from fields in a data source. It serializes that content as JSON documents and hands-off those documents to the search engine for indexing. 
To create an indexer for text content, what are the required properties that you need? (select three answer choices)

Answer options:

A.dataSourceName
B.searchIndexerClient
C.targetIndexName
D.name
E.fieldMappings

Correct Answers: A, C and D
Option A is correct because dataSourceName provides a string value for an existing data source.
Option B is incorrect because searchIndexerClient is a method, not a property used while creating an index for text content.
Option C is correct because targetIndexName provides a string value for the name of an existing index.
Option D is correct because the name is the required property that provides string value to uniquely identify the indexer.
Option E is incorrect because fieldMappings is an optional property while creating an indexer got text content.
Reference:
To learn more about creating an indexer, use the link given below: 

https://docs.microsoft.com/en-us/azure/search/search-howto-create-indexers