A diver looking up through the water sees the outside world contained in a circular horizon, the refractive index of water is \[\frac{4}{3}\], and the diver's eyes are 15 cm below the surface of water. Then the radius of the circle is:

• A. \[15\times 3\times \sqrt{5}cm\]
• B. \[15\times 3\sqrt{7}cm\]
• C. \[\frac{15\times \sqrt{7}}{3}cm\]
• D. \[\frac{15\times 3}{\sqrt{7}}cm\]