A) \( \Large x_{1}y_{2}+x_{2}y_{1} \) |
B) \( \Large \left(x^{2}_{1}+x^{2}_{2}+y^{2}_{2}\right) \) |
C) \( \Large \left(x_{1}-x_{2}\right)^{2}+ \left(y_{1}-y_{2}\right)^{2} \) |
D) \( \Large x_{1}x_{2}+y_{1}y_{2} \) |
D) \( \Large x_{1}x_{2}+y_{1}y_{2} \) |