Concept:
- A water image (reflection in still water) is a top-to-bottom flip along the horizontal line MM': whatever is at the top of the figure appears at the bottom of the image and vice versa, while left and right stay exactly where they were.
- Every arrow must reverse its up/down direction, and a circle shaded on one half must have its shaded half move from bottom to top (or top to bottom).
Step 1: Study the structure of the original triangle.
The large upward-pointing triangle is split into 4 smaller triangles: the top small triangle holds an upward arrow, the bottom-left holds a circle shaded on its lower half, the bottom-right holds a diagonal arrow pointing down-right, and the middle (upside-down) triangle holds a downward arrow.
Step 2: Flip the whole triangle top to bottom.
After reflecting along the horizontal line MM', the entire triangle turns upside down, so its apex now points downward; the region that was the "top small triangle" now sits at the very bottom tip, and the old "bottom row" now sits at the top.
Step 3: Reverse every internal detail vertically.
The upward arrow becomes a downward arrow and moves to the bottom tip.
The downward arrow becomes an upward arrow and sits in the middle.
The down-right diagonal arrow becomes an up-right diagonal arrow.
The circle's shaded lower half becomes a shaded upper half.
Step 4: Match this fully-reversed figure with the options.
Only one option shows all four of these reversed features together at the correct positions; the rest keep at least one arrow direction or the shaded half of the circle un-reversed.
Final Answer: Option 2