Y = C + S
So for year 1 Y = 150, year 2 Y = 350 and year 3 Y = 550.
Going off this, we can now find MPC and MPS for year 1, 2 and 3 in order to find the value of the multiplier ... k = 1/mps or k=1/(1-mpc)
As you can see from the data, the change in consumption (C) and savings (S) is both 100, and the change in income (Y) is 200.
Therefore, k = 1/0/5
k=2, which gievs you D