Final answer:
The correct synonym for "twinkle" as a noun is "scintillation". For the loudness of sound, the correct term is "intensity level" or "decibel". Other options do not accurately describe these concepts.
Step-by-step explanation:
The word that can be used as a synonym for "twinkle" (n.) is scintillation. Therefore, the correct answer is a) Scintillation. Neither spinning, distortion, nor whorl appropriately captures the meaning associated with a small flash of light or a slight and rapid shining, which "twinkle" conveys. Scintillation refers to the flash or sparkle of light, often associated with stars, which closely matches the meaning of twinkle.
As for the terms related to sound, the word or phrase used to describe the loudness of sound is intensity level or decibel. Hence, the correct option would be b) intensity level or decibel. Frequency or oscillation relates to the number of waves that pass a point in a certain period and is associated with pitch, timbre refers to the quality or color of a sound that makes it unique, while pitch refers to how high or low a sound is perceived to be.