A user issues the following cURL command to encrypt data using the transit engine and...

The payload.json file that has the correct contents is C. This file contains a JSON object with a single key, “plaintext”, and a value that is the base64-encoded string of the data to be encrypted.  This is the format that the Vault API expects for the transit encrypt endpoint 1 . The other files are not correct because they either have the wrong key name, the wrong value format, or the wrong JSON syntax.