A hemispherical depression is cut out from one face of a cubical wooden block such that the diameter l cm of the hemisphere is equal to the edge of the cube. Determine the surface area of the remaining solid.

• A. \(\frac{1}{2}{l^2}\left( {12 + \pi } \right)c{m^2}\)
• B. \(\frac{1}{4}{l^2}\left( {24 + \pi } \right)c{m^2}\)
• C. \(\frac{1}{3}{l^2}\left( {18 + \pi } \right)c{m^2}\)
• D. \(\frac{1}{4}{l^2}\left( {18 + \pi } \right)c{m^2}\)