Answer: Option 'D' is correct.
Step-by-step explanation:
Since we have given the figure:
At point A, we get that
At price $5, quantity demanded is 1 unit.
At price $4, quantity demanded is 2 units.
So, here demand is changing due to change in price.
So, it would be considered as <u>"Change in quantity demanded".</u>
So, It is increase in quantity demanded due to fall in price.
So, there is a shift from point A to point B.
Hence, Option 'D' is correct.