Answer:
a.) high amplitude, high frequency
Step-by-step explanation:
Frequency and amplitude are properties of sound. Varying these properties changes how people perceive sound.
While hearing sound of a particular frequency we call it pitch i.e., the perception of a frequency of sound.
High pitch means high frequency and high frequency is perceived to have a shrill sound.
The loudness of a sound is measured by the intensity of sound i.e., the energy the sound possesses per unit area. As the amplitude increases the intensity increases. So, a loud sound will have higher density.
Hence, the loud shrill whistle will have high frequency and high amplitude.