Concept:A pipette is calibrated to deliver one exact volume with high precision.Explanation:A beaker and a conical flask are not designed for accurate volume measurement.Their graduation marks give only approximate readings.A measuring cylinder can measure different volumes, but its accuracy is lower.A pipette measures a single specific volume, such as 25.0cm3, very accurately.Therefore, the pipette is the correct apparatus for this purpose.Answer:D. Pipette