Option 1 -> Affordability (income) directly affects how much an individual can and will demand.
Option 2 -> Price of substitutes influences individual demand as consumers may switch between goods.
Option 3 -> Tastes and preferences are key determinants of what an individual chooses to demand.
Option 4 -> Number of consumers affects market demand, not individual demand.
Hence, Number of consumers -> Individual demand represents the quantity demanded by a single consumer based on their own income, preferences, and prices. The number of consumers in the market is a factor that determines market demand (aggregate demand), but it does not influence one individual's demand decision. An individual's demand curve is independent of how many other consumers exist in the market. -> correct