The correct answer is option 2: Water.

Density is defined as the mass of a substance per unit volume. In simple terms, it is a measure of how much mass is packed into a given volume of a substance.

Water is known for its unique properties, one of which is its density behavior. At most temperatures, water`s density decreases as it heats up and expands. However, when water is cooled below 4 degrees Celsius (39 degrees Fahrenheit), its density starts to increase as it continues to cool.

This increase in density continues until it reaches its maximum density at 4 degrees Celsius. This means that the mass of water per unit volume is the greatest at this temperature.

Chloroform (option 1), benzene (option 3), and ice (option 4) do not have the same density behavior as water. While they may have different densities at different temperatures, none of them exhibit this unique maximum density behavior.

In summary, water has the maximum density among the given options, occurring at 4 degrees Celsius.