When two breath samples are taken, how is the evidential reading determined?

Answer: C — The lower reading used.

When two breath samples are taken for evidential purposes, the reading used is the lower of the two. This conservative approach accounts for slight variations that can occur between samples due to technique, residual mouth alcohol, or device fluctuation. By selecting the lower value, the measurement is less likely to overstate impairment from a transient or technical factor, ensuring the result reflects the more cautious assessment of BAC. Using an average could push the result higher than the actual consistent reading, while using the higher reading could unfairly penalize someone for a momentary spike. Neither reading is not appropriate because there is an evidential value from the breath test that should be applied.