Final answer:
The demand curve for a normal good will shift to the right due to an increase in income, an increase in population, and an increase in the price of substitute goods; therefore, the correct answer is 'd) all the above'.
Step-by-step explanation:
The demand curve for a normal good will shift to the right if a) income increases, b) population increases, or c) the price of a substitute good increases. All these factors can cause the demand for a normal good to rise, which is represented graphically as a shift to the right of the demand curve.
When income rises for a normal good, people can afford to buy more of that good, leading to an increase in demand. Similarly, if the population likely to buy the product grows, the total demand will likely increase as more consumers enter the market. Lastly, if the price of substitute goods rises, consumers may switch to the normal good, increasing its demand. Hence, the correct answer to the question would be d) all the above.