A. Incorrect. Pulling the child's earlobe down and back is a technique used for straightening the ear canal in older children and adults, not for using a tympanic thermometer.

B. Correct. When using a tympanic thermometer, it's important to gently insert the probe into the ear canal and ensure a proper seal. This helps to obtain an accurate temperature reading.

C. Incorrect. Holding the thermometer in place for 1-2 minutes is not the correct technique for tympanic temperature measurement. It may lead to an inaccurate reading.

D. Incorrect. Using an oral thermometer for a 2-year-old child is not the recommended method, as it may not provide an accurate temperature reading.