Which of the following methods for preparing a 0.0010 F solution from a 1.0 F stock solution provides the smallest overall uncertainty?

A) A one-step dilution using a 1-mL pipet and a 1000-mL volumetric flask.

B) A two-step dilution using a 20 mL pipet and a 1000 mL volumetric flask for the first dilutions and a 25 mL pipet and a 500 mL volumetric flask for the second dilution.

Random Uncertainties for glassware:

1 mL pipet: 0.0006 mL

20 mL pipet: 0.03 mL

25 mL pipet: 0.03 mL

500 mL volumetric flask: 0.2 mL

1000 mL volumetric flask: 0.3 mL