The angle of depression made by the bird to the mouse is seen on the attached image. We can find the distance from the field mouse up to the bird's eye by getting the hypotenuse of the triangle formed. Using the CAH in Pythagorean Theorem, we will have:
cos ∅ = adjacent / hypotenuse
cos 65 = 30 / h
h = 70.98 ≈ 71 m ⇒ the answer is D
