\[\sqrt{\mathbf{28}\frac{\mathbf{4}}{\mathbf{9}}}\mathbf{-}\sqrt{\mathbf{30}\frac{\mathbf{1}}{\mathbf{4}}}\] is equal to ____.

• A. \[\frac{1}{2}\]
• B. \[\frac{-1}{6}\]
• C. \[\frac{1}{6}\]
• D. \[\frac{1}{3}\]