Work done = pressure × volume change (ΔV = area × distance)

Steps:

• Convert area to m²: 500 cm² = 0.05 m² (1 m² = 10,000 cm²).
• Convert distance to m: 3 cm = 0.03 m.
• Calculate ΔV = 0.05 m² × 0.03 m = 0.0015 m³.
• Calculate work W = 400 Pa × 0.0015 m³ = 60 J.

Why A is correct:

• By the formula for work against constant pressure, W = P ΔV, where ΔV is the displaced volume in SI units.

Why the others are wrong:

• B overestimates by factor of 10, likely from using cm for distance without conversion.
• C overestimates by factor of 100, likely from using cm² for area without conversion.
• D overestimates by factor of 1000, likely from ignoring both area and distance conversions.

Final answer: A