Which term describes the indirect variation in real income caused by changes in the price of a good affecting the quantity demanded?

Explanation

The question refers to the implicit alteration in real income due to price changes influencing demand. This phenomenon is known as the labour effect, which captures changes related to labor inputs or costs affecting demand indirectly. The income effect relates directly to changes in purchasing power, while the substitution effect involves replacing one good with another. Therefore, the correct answer is the labour effect.