A beam of monochromatic light is incident at \[i={{50}^{o}}\] on one face of an equilateral prism the angle of emergence is \[40{}^\circ ,\] then the angle of minimum deviation is-

• A. \[{{30}^{o}}\]
• B. \[<{{30}^{o}}\]
• C. \[\le {{30}^{o}}\]
• D. \[\ge {{30}^{o}}\]