Final answer:
The correct technique for palpating a client's uterine contractions is by palpating with one hand over the fundus, which allows for effective assessment.
Step-by-step explanation:
The nurse would determine that the staff member is using the correct technique for palpating a client’s uterine contractions if a) the observation made is palpating with one hand over the fundus. This method allows assessment of the contraction’s strength, duration, and frequency effectively. Techniques such as b) pressing firmly with fingertips on the abdomen can lead to discomfort and may not accurately gauge the contractions, while c) monitoring contractions continuously with a Doppler is usually not used for palpation of contractions. Using both hands to assess uterine tone on each side of the abdomen as mentioned in d) may be used for other assessments but is not the standard for palpating uterine contractions.