Final answer:
The triple point of water occurs at a temperature of 273.16 K (0.01°C) and a pressure of 611.2 Pa, where ice, liquid water, and water vapor coexist in equilibrium. Hence, the correct answer is option (3).
Step-by-step explanation:
The triple point of a substance is a specific temperature and pressure at which the solid, liquid, and gas phases of the substance are in equilibrium. For water, the triple point occurs at a precise temperature and pressure that is different from the conditions where just two of the states are in equilibrium (for example, the melting or boiling point).
The triple point of water is not at 0°C and 1 atm (the melting point) or 100°C and 1 atm (the boiling point); rather, it is at a temperature of 273.16 K (0.01°C) with a pressure of 611.2 Pa. This combination of temperature and pressure allows solid ice, liquid water, and water vapor to coexist in a stable equilibrium.