O <br /> r <br /> 0) <br /> O <br /> 0 <br /> 0 <br /> O <br /> 0 <br /> 0 <br /> 0 <br /> 0 <br /> 0 <br /> 0 <br /> 0 <br /> 0 <br /> to <br /> 0 <br /> at <br /> 0 <br /> c) <br /> ie <br /> v <br /> 0 <br />