Answer:
Step-by-step explanation:
If the diagonals of the rectangle are congruent,
AC = BD
By using formula to calculate the distance between two points,
Distance between two points = 
Distance between A(0, -3) and C(2, 8),
AC = 
= 
= 
Similarly, distance between two points B(-4, 0) and D(6, 5),
BD = 
= 
= 
Therefore, both the diagonals are congruent.
Hence, given quadrilateral ABCD is a rectangle.