$\begin {array} {1 1} (A)\;Both\: the\: length\: and\: the\: radius\: were\: halved \\ (B)\;Both\: the\: length \: and \: the \: radius\: were \: doubled \\ (C)\;The\: radius \: is \: doubled \\ (D)\;The\: length\: is\: doubled \end {array}$