Correct Answer - B
The construction and calibration of a celsius thermometer involves the following steps. Take a thick walled capillary tube with thin walled glass bulb and fill the bulb with mercury using a funnel (c) from one end and while filling it with the mercury place the glass bulb in a hot oil bath to remove the air bubbles (e), now mark the lower fixing point by placing the bulb in melting ice taken in a funnel (a). Mark the upper fixing point with the help of hypsometer. (d). The distance between the two fixed poitns is called fundamental interval. in celsium scale the fundamental interval is divided into 100 equal divisions and it is calibrated (b).