The correct answer is C. Gaussian.
A Gaussian pulse is a type of pulse that has a Gaussian amplitude envelope. The amplitude spectrum of a Gaussian pulse is also a Gaussian function. This means that the amplitude of the pulse at any frequency is proportional to the Gaussian function of that frequency.
The Gaussian function is a bell-shaped curve that has a maximum value at the center and decreases towards zero as the frequency increases. This means that the amplitude of the Gaussian pulse is highest at the center of the pulse and decreases towards zero as the pulse gets wider.
The Gaussian pulse is a common type of pulse that is used in many applications, such as communication systems and signal processing. It is a very versatile type of pulse that can be used to represent a wide variety of signals.
The other options are incorrect. Option A is incorrect because the amplitude spectrum of a Gaussian pulse is not uniform. Option B is incorrect because the amplitude spectrum of a Gaussian pulse is not a sine function. Option D is incorrect because the amplitude spectrum of a Gaussian pulse is not an impulse function.