The displacement of the pictured position of a point of h elevation on a vertical photograph taken with a camera of 30 cm focal length, from an altitude of 3000 m, is A. 4.4 mm B. 5.5 mm C. 6.5 mm D. 7.5 mm

4.4 mm
5.5 mm
6.5 mm
7.5 mm

The correct answer is $\boxed{\text{A}}$.

The displacement of the pictured position of a point of h elevation on a vertical photograph taken with a camera of 30 cm focal length, from an altitude of 3000 m, is given by the following formula:

$$d = \frac{h}{f} \tan \theta$$

where $h$ is the elevation of the point, $f$ is the focal length of the camera, and $\theta$ is the angle of view of the camera.

In this case, $h = 3000$ m, $f = 30$ cm, and $\theta = 60^\circ$. Substituting these values into the formula, we get:

$$d = \frac{3000 \text{ m}}{30 \text{ cm}} \tan 60^\circ = 4.4 \text{ mm}$$

Therefore, the displacement of the pictured position of a point of h elevation on a vertical photograph taken with a camera of 30 cm focal length, from an altitude of 3000 m, is 4.4 mm.

Option A is the correct answer because it is the only option that is within the range of possible values for the displacement. The other options are too large or too small.