C: textType is an optional parameter. It defines whether the text being translated is plain text or HTML text (used for web pages).
D: to is a required parameter. It specifies the language of the output text. The target language must be one of the supported languages included in the translation scope.
F: toScript is an optional parameter. It specifies the script of the translated text. We use Latin (Roman alphabet) script.
Reference:
https://docs.microsoft.com/en-us/azure/cognitive-services/translator/reference/v3-0-translate