Answer :
[tex]A(x_A;\ y_A);\ B(x_B;\ y_B)\\\\midpoint\ AB:\left(\frac{x_A+x_B}{2};\ \frac{y_A+y_B}{2}\right)\\\\-------------------\\\\(-3;\ 0);\ (7;\ 4)\\\\midpoint:\left(\frac{-3+7}{2};\ \frac{0+4}{2}\right)\to\left(\frac{4}{2};\ \frac{4}{2}\right)\to(2;\ 2)\\\\Answer:A[/tex]