The correct option out of the given choices is option 1. It states that the density of water at 4°C is 1000 kg/m3.

Density is a measure of how much mass is contained within a given volume. Different temperatures can affect the density of a substance, including water.

At 4°C, water reaches its maximum density. This means that at this temperature, water is most compact and has the highest mass per unit volume. The density of water at 4°C is indeed around 1000 kg/m3.

Option 2, which suggests that the density of water at 0°C is 1000 kg/m3, is incorrect. At 0°C, water freezes and turns into ice, causing its density to decrease. Ice has a lower density than liquid water, which is why it floats on top of it.

Option 3, stating that the density of water at 0°C is 100 kg/m3, is also incorrect. This value is significantly lower than the actual density of water at any temperature.

Finally, option 4, suggesting that the density of water at 4°C is 10 kg/m3, is incorrect as well. This value is much lower than the actual density of water at that temperature