The correct answer is $\boxed{\text{A}}$.
A wind rose is a circular diagram that shows the direction of the wind. The longest line on a wind rose represents the direction from which the wind blows most often. In this case, the longest line is S 45° E, which means that the wind blows most often from the southeast.
The bearing of a runway is the direction in which the runway is aligned. The bearing is measured in degrees from true north, with 0° being due north, 90° being due east, 180° being due south, and 270° being due west.
In this case, the bearing of the runway is 135°. This is because the runway is aligned 45° east of south.
Option $\boxed{\text{A}}$ is the correct answer because it is the bearing of the runway. Option $\boxed{\text{B}}$ is incorrect because it is the bearing of the wind. Option $\boxed{\text{C}}$ is incorrect because it is not a valid bearing. Option $\boxed{\text{D}}$ is incorrect because it is not a valid bearing. Option $\boxed{\text{E}}$ is incorrect because it is not the only correct answer.