Answer:
Option B is not a justification
Step-by-step explanation:
Option A is a justification (to get two pair of similar triangles (ABC-ACD) and (ABC-BCD))
Option C is a justification (a^2 = cy, b^2 = cx, a^2 + b^2 = cy + cx)
Option D is a justification (a^2 + b^2 = cy + cx = c(y + x) = c^2)
=> Option B is not a justification