If a vertex of a triangle is (1, 1) and the midpoints of two sides of the triangle through this vertex are (-1, 2) and (3, 2), then the centroid of the triangle is
1
\(\left( { - \frac{1}{3},\frac{7}{3}} \right)\)
2
\(\left( { - 1,\frac{7}{3}} \right)\)
3
\(\left( {\frac{1}{3},\frac{7}{3}} \right)\)
4
\(\left( {1,\frac{7}{3}} \right)\)