Identify the correct statement from among the following :

A laboratory (general-purpose) thermometer and a clinical (body-temperature) thermometer are both mercury-in-glass thermometers built for very different jobs. A clinical thermometer's scale covers only the narrow band around normal body temperature and has a kink (constriction) near the bulb so the mercury thread does not fall back once it is removed from the body; a laboratory thermometer has no such constriction, and its scale is built to record a much wider range of temperatures for general scientific use.

1. A liquid at its boiling point (around 100 °C for water) lies far outside the narrow body-temperature scale of a clinical thermometer, so a clinical thermometer cannot be used to record it.

2. The 'room' thermometer named here is a separate device used to monitor ambient/room temperature — distinct from both the clinical and the laboratory instrument — with a commonly quoted scale of about 20 °C to 50 °C, not 30 °C to 100 °C, so this option misstates its range.

3. A scale of about 35 °C–42 °C belongs to the body-temperature instrument, not the general-purpose one — assigning it to the general-purpose instrument reverses which scale belongs to which device.

4. Comparing the two actual scales: the general-purpose instrument's scale spans roughly 120 degrees (about −10 °C to 110 °C) while the body-temperature instrument's scale spans only about 7 degrees (35 °C to 42 °C) — the general-purpose instrument's range is clearly the larger of the two.

Cross-check by lining up the two scales directly:

This matches how these two instruments are actually built and used: the statement comparing the two ranges — that the general-purpose instrument's range is greater than the body-temperature instrument's range — is the one consistent with their actual scales.