Which HTTP status means that the origin server knows the method that is received in the request line, but the target resource does not support the method?

105 is not a valid HTTP status code - the 1xx range contains only informational responses such as 100 Continue and 101 Switching Protocols.

205 Reset Content is a 2xx success response indicating the client should reset the document view, unrelated to unsupported methods.

305 Use Proxy is a deprecated 3xx redirect response and has no relation to whether a resource supports a given method.

HTTP 405 Method Not Allowed is a client error response indicating the origin server recognizes the HTTP method in the request line (such as PUT or DELETE) but the specific resource identified by the URI does not support that method. The server is required to include an Allow header listing the methods the resource does support. This status is defined in RFC 9110 as a 4xx client error.