Datetime is the correct answer because Azure Cosmos DB does not provide a native DateTime type in its JSON document model.

Azure Cosmos DB stores data as JSON documents and supports native JSON types such as numbers strings booleans arrays objects and null. Because of this there is no dedicated Datetime value type and dates are typically stored as ISO 8601 strings or as epoch numbers depending on the application and query needs.

Number is incorrect because Cosmos DB supports numeric values as JSON numbers and handles integers and floating point values natively.

String is incorrect because string values are a native JSON type in Cosmos DB and are commonly used to store textual data and date strings when needed.

Boolean is incorrect because boolean values are part of the JSON data model and are supported directly by Cosmos DB.

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