Answer:
The correct option is D.
Step-by-step explanation:
Demand curve is a curve which is depicted in the form of graph and the relationship among the price of a commodity and the quantity of that commodity will be demanded at that price.
Loanable funds are those funds or income of people which they choose to save and lent out instead of using for own consumption.
The demand curve shifts due to change in the price and that causes change in quantity demanded. Shift of demand curve from D1 to D2 means that there is an increase in demand for the loanable funds and this increase is originate from people who have extra income and that they want to lent out.
Therefore, the correct option is D