Final answer:
Option c, y = cos(x) - 2, is a sinusoid.
Step-by-step explanation:
A sinusoid is a mathematical function that represents a waveform. It has a characteristic shape that repeats itself over a certain period of time. Out of the given options, the only one that represents a sinusoid is option c. The function y = cos(x) - 2 represents a cosine wave, which is a type of sinusoid.