Classify the following sets of measurements as accurate, precise, both, or neither.

(a) Checking for consistency in the weight of chocolate chip cookies: $17.27 \mathrm{g}, 13.05 \mathrm{g}, 19.46 \mathrm{g}, 16.92 \mathrm{g}$

(b) Testing the volume of a batch of $25-\mathrm{mL}$ pipettes: $27.02 \mathrm{mL}, 26.99 \mathrm{mL}, 26.97 \mathrm{mL}, 27.01 \mathrm{mL}$

(c) Determining the purity of gold: $99.9999 \%, 99.9998 \%, 9999 \%, 99.9999 \%$