Answer:
B
Step-by-step explanation:
Given 2 quantities that vary directly, then the graph must pass through the origin.
Nikiya's graph is the only one to do this ⇒ B
To answer this question you should begin with the coin that has a higher value. If you start with the dime and then just add the correct number of pennies to total $0.40, you will see that you will need 3 dimes ($0.30) and 10 pennies ($0.10).
I used a guess and check strategy starting with 2 dimes.
I would say that the unfinished puzzle has more than one piece and the missing piece is only one, itself.