In a DELETE Request, What Would Omitting the Value of _Key

In a DELETE request, what would omitting the value of _key from the REST endpoint do?

A) Clean the KV store, deleting all content.
B) Produce the syntax error "Key value missing" . Produce the syntax error "Key value missing" .
C) Cause all records in a collection to be deleted.
D) Mean that the _key value must be passed as an argument. Mean that the value must be passed as an argument.