Why does demand not change when the price of a good changes

Why does demand not change when the price of a good changes with no change in the other influences on buying plans? Consider the demand for pastapasta. The demand for pastapasta does not change when a change in _______ occurs. A. the expected future price of pastaexpected future price of pasta B. the price of pasta saucepasta sauce (pasta saucepasta sauce is a complementis a complement of pastapasta) C. the populationpopulation D. the price of pasta

Solution

The demand for good might be completely inelastic (price inelastic)

The price of pasta because pasta and pastapasta are apparently different commodities. Please mention if you have made mistake in writing things