Ratio of \[\left( \frac{\mathbf{1}}{\mathbf{3}}\,\,\mathbf{of}\,\,\mathbf{21}\,\,\mathbf{liters} \right)\] to \[\left( \mathbf{1}\mathbf{.5}\,\,\mathbf{of}\,\,\frac{\mathbf{1}}{\mathbf{2}}\,\,\,\mathbf{liters} \right)\] is:

• A.  \[6:21\]
• B.  \[1:24\]
• C.  \[28:3\]
• D.  \[3:26\]
• E.  None of these