A triangle has a vertex at (1, 2) and the mid points of the two sides through it are (-1, 1) and (2, 3). Then the centroid of this triangle is:

**\(\left( {1,\;\frac{7}{3}} \right)\) **
**\(\left( {\frac{1}{3},{\rm{\;}}2} \right)\) **
**\(\left( {\frac{1}{3},{\rm{\;}}1} \right)\) **
**\(\left( {\frac{1}{3},{\rm{\;}}\frac{5}{3}} \right)\) **