Correct answer: 2 mm, 4.5 mm, 12 mm
The shift of a point equals the cumulative extension of the supporting members above it. Computing dL = F*L/(A*Y) for each segment and summing cumulatively gives shifts in the ratio 4: 9: 24, and the magnitudes matching the loaded data give 2 mm, 4.5 mm and 12 mm at B, C and D.