hey!!
here is your answer >>>
A rectangle has all the angles as 90°
so the puthogoreus theorm can be applied,
base = 12.75
height = 17
hypotenuse = ?
THEORM => (hypotenuse)^2 = (base)^2 + (height)^2
(hyp)^2 = 162.56 + 289
(hyp)^2 = 451.56
hyp = √451.56
= 21.249
diagnol according to the options is 21.25!.
Hope my answer helps!