A series of figures is shown below. Study how the pattern changes from one figure to the next, then pick the figure that should replace the question mark.
Show Hint
Count how many horizontal and vertical lines each figure loses compared to the one before it.
Instead of counting forward, count backward from each answer choice to see which one continues the shrinking grid pattern.
Lone horizontal line: has 1 horizontal and 0 vertical lines, which is the reverse of what the series needs, since the series keeps a vertical line while dropping horizontals, so this is rejected.
Small grid: still keeps 2 lines each direction, the same count as figure 2, so it does not continue the drop and is rejected.
Single vertical stroke: has 0 horizontal and exactly 1 vertical line, continuing the exact one fewer of each drop seen from figure 1 to figure 3, and it is the only option matching this rule.
Plus sign: has 1 horizontal and 1 vertical line, which would fit as figure 3 again, not a new step forward, so it is rejected.
Only the single vertical stroke continues the minus one, minus one rule to its natural end at 0 horizontal lines.
Let's summarize:
Figures lose one horizontal and one vertical line each step.
The fourth figure needs 0 horizontal and 1 vertical line.
Only the plain vertical stroke fits this count.
So the completing figure is option 3.
\[ \boxed{\text{Option 3, a single vertical line}} \]
