A hollow cylindrical iron pipe of length 1.4 m has bore radius 2.5 cm and thickness of the metal is 1 cm. What is the volume of the iron used in the pipe?

For a hollow cylinder, the volume of material = π(R² - r²)h, where R is outer radius, r is inner radius (bore radius). Inner radius = 2.5 cm. Thickness = 1 cm, so outer radius = 2.5 + 1 = 3.5 cm. Length = 1.4 m = 140 cm. Volume = π[(3.5)² - (2.5)²] × 140 = π[12.25 - 6.25] × 140 = π(6) × 140 = 840π ≈ 2638.9 cm³. Rounding gives approximately 2640 cm³. Option B has incorrect digit order, while option C has different values.