I will explain the concept of elasticity to you so that *you* will be able to answer this question. Elasticity refers to the change in demand for a product based on the change in price. If a product has high elasticity, the demand for it will change dramatically if the prices goes up or down. If a product has low elasticity, the demand for it will not change dramatically if prices go up or down. I'll give you a good example of a product with relatively low elasticity - one that's been in the news a lot over the past few years: Gasoline. Gasoline has relatively low elasticity because, even though prices change dramatically (usually to the high side), people *need* this product in order to operate their motorized vehicles. And there are very few substitute products to use in its place.
....That last point that I made is a very important factor in determining a product's elasticity. In other words, if there are basically no substitute items for a given product - and that product is necessary - elasticity will be low.
So, the thing you want to ask yourself regarding your question is: Which one of those products would people just leave on the shelf if they raised the price over a given amount of time? Or.... which one would 'fly off' the shelf if they lowered the price over a given amount of time? The answer to either of those questions would represent a product with high elasticity.
