Answer:
D. [tex]\sqrt{65}[/tex]
Step-by-step explanation:
The computation of the length of a diagonal (AC or BD) of the rectangle is shown below:
As we know that
The Diagonal length of AC is
[tex]= (x_2 - x_1)^2 + (y_2 - y_1)^2\\\\= (9 -2)^2 + (8 - 4)^2\\\\= (7)^2 + (4)^2[/tex]
[tex]= \sqrt{49 + 16}\\\\= \sqrt{65}[/tex]
Therefore correct option is D.