What is the numerical aperture of the fiber if the angle of acceptance is 16 degree?

The numerical aperture (NA) of an optical fiber is a measure of how well the fiber can accept light. It is defined as the sine of the half-angle of the cone of light that can be accepted by the fiber. The NA is related to the angle of acceptance, $\theta$, by the equation

$$NA = \sin \theta$$

In this case, the angle of acceptance is 16 degrees, so the numerical aperture is

$$NA = \sin 16^\circ = 0.27$$

Therefore, the correct answer is $\boxed{\text{D}}$.

The other options are incorrect because they do not correspond to the given angle of acceptance.