Which of the following has the least number of sides?

The shape with the least number of sides among the given options is a hexagon. A hexagon has six sides, while the other shapes have more: a heptagon has seven sides, a nonagon has nine sides, and a decagon has ten sides. Therefore, when comparing the number of sides, the hexagon clearly stands out as having the fewest. This distinction is fundamental in understanding polygon classifications, as the names of polygons are derived from Greek numerical prefixes that indicate the number of sides. Recognizing these patterns helps in identifying and distinguishing between different polygons effectively.