Four pairs of words are given. Find the odd one out. A. Rhombus : Four-sided polygon B. Nonagon : Seven-sided polygon C. Octagon : Eight-sided polygon D. Hexagon : Six-sided polygon

A rhombus is a four-sided polygon, an octagon has eight sides and a hexagon six, so those pairs are correct. A nonagon has nine sides, not seven (a seven-sided polygon is a heptagon), so 'Nonagon : Seven-sided polygon' is the odd, incorrect pair.