Which of the following is an example of a simple carbohydrate?

The correct choice is pasta, as it is classified as a simple carbohydrate, particularly when it refers to products made from white flour. Simple carbohydrates are typically composed of one or two sugar molecules and are quickly digested, leading to rapid spikes in blood sugar levels. In this context, pasta, especially the more refined forms, falls into this category because it is made from simple sugars and often lacks the fiber found in whole grains.

On the other hand, options such as rice, quinoa, and brown bread can all contain more complex carbohydrates. Complex carbohydrates are made up of longer chains of sugar molecules, which take longer to digest, providing a more gradual release of energy. These foods generally have more fiber and nutrients, contributing to a slower rise in blood sugar compared to simple carbohydrates. While there can be variations in the preparation and type of these foods, pasta is generally recognized as falling under the category of simple carbs, especially in its more refined forms.