An engineer is using REST API calls to configure Cisco APIC.

Cisco APIC accepts a properly structured JSON authentication payload containing an aaaUser managed object and an attributes object. The username and password must be represented as valid quoted JSON name-value pairs. Option C follows valid JSON syntax and supplies both required authentication attributes. Option A resembles a JavaScript object literal but is not valid JSON because its property names and string values are not enclosed in quotation marks. Options B and D attempt to use XML, but their element and attribute structures do not match the required APIC XML authentication format. The JSON payload is sent through an HTTP POST request to the APIC login URI. If authentication succeeds, APIC returns an aaaLogin response containing a token. That token is then presented with subsequent API requests to maintain the authenticated management session.