Step 1: Observe the figure.
The given figure shows a pipe carrying steady incompressible fluid. Between points A and D, the Total Energy Line (TEL) and Hydraulic Grade Line (HGL) are drawn. The slope of TEL and HGL reflects changes in velocity head and pressure head due to varying pipe geometry.
Step 2: From A to B.
The TEL and HGL show a steep drop between A and B. This indicates that velocity increases while pressure decreases.
According to Bernoulli’s principle, such a rise in velocity occurs when the pipe converges.
So, A–B is a converging section.
Step 3: From B to C.
Between B and C, the TEL and HGL remain nearly parallel and constant in slope. This suggests velocity and pressure are not changing significantly.
Hence, the pipe cross-sectional area must be constant.
So, B–C is a constant area section.
Step 4: From C to D.
Between C and D, the TEL and HGL rise relative to the flow direction, showing a reduction in velocity and recovery of pressure.
This corresponds to a diverging section.
So, C–D is a diverging section.
Step 5: Match with options.
Thus, the sequence is:
\[
\text{A–B: Converging, B–C: Constant area, C–D: Diverging}.
\]
This matches option (A).
Final Answer:
\[
\boxed{\text{Converging, Constant area, Diverging}}
\]