Which of the following is NOT a condition in the concept of demand?

The concept of demand is fundamentally linked to the relationship between consumers' willingness and ability to purchase goods or services. The conditions that directly influence this demand typically include the price of the good or service, consumers' income and wealth, and demographic factors like population.

The price of the good or service is crucial; as prices change, they directly affect consumer demand—usually, higher prices result in lower demand, and lower prices increase demand. Income and wealth affect how much consumers can afford, thus influencing their demand for goods and services. Similarly, population size and demographics can alter demand as different groups have different purchasing behaviors.

Technology, while it can impact production and the availability of goods, does not directly factor into the basic calculations of demand itself. Instead, technology typically influences supply side dynamics and may affect how demand is expressed over time or how goods are consumed, but it is not a core condition of demand as defined by standard economic principles. Therefore, it is the correct answer to identify as NOT being a condition in the concept of demand.