Option 1 states that the value of water will increase when heated from 0°C to 20°C. This option is incorrect because as water is heated, its volume expands and the density decreases, causing the value to decrease.

Option 2 states that the value of water will decrease when heated from 0°C to 20°C. This option is incorrect because the value of water does not solely depend on temperature. Other factors such as pressure and impurities can affect the value of water.

Option 3 states that the value of water will first increase and then decrease when heated from 0°C to 20°C. This option is incorrect because the value of water does not follow a specific pattern of increasing and then decreasing with temperature.

The correct answer is option 4, which states that the value of water will first decrease and then increase when heated from 0°C to 20°C. This is because as water is heated, the density initially decreases causing the value to decrease. However, as the temperature continues to increase, the density starts to increase again, resulting in an overall increase in the value of water.