Answer:
A digital thermometer
Step-by-step explanation:
A bulb thermometer is the thermometer which consists a bulb at the one end and mercury at the other. It consists capillary tube in which mercury rise. It accuracy is based on the observer observation.
A digital thermometer is the thermometer which are sensibly portable and it has a digital screen. It will give the accurate value of temperature.
In the given problem the bulb thermometer gives 21°C of an indoor reading while digital in the same room gives a reading of 20.7°C. In this it can be seen that the bulb reading is up to 2 significant digit and the digital thermometer reading is up to 3 significant digits.
Therefore, a digital thermometer is more precise.