I need help with this question please

Answer:
C.
Step-by-step explanation:
Given
[tex]A =(x_1,y_1)[/tex]
[tex]B =(x_2,y_2)[/tex]
[tex]C =(x_3,y_3)[/tex]
[tex]D =(x_4,y_4)[/tex]
Required:
Which condition proves that AB is perpendicular to CD
First, calculate the slopes of both.
For AB
[tex]m_1 = \frac{y_2 -y_1}{x_2 - x_1}[/tex]
For CD
[tex]m_2 = \frac{y_4 -y_3}{x_4 - x_2}[/tex]
The condition of perpendicularity is:
[tex]m_1 * m_2 = -1[/tex]
Substitute values for m1 and m2
[tex]\frac{y_2 -y_1}{x_2 - x_1} * \frac{y_4 -y_3}{x_4 - x_2} = -1[/tex]
Option (c) is correct