Final answer:
Without additional context regarding how the depth of the water changes over time, it's not possible to confidently select the correct equation that models the depth as a function of time.
Step-by-step explanation:
To choose the equation that best models the depth of the water as a function of time, where y is depth and x is time in hours, we would need additional context that describes the relationship between the depth and time. For example, if the depth of the water increases at a constant rate over time, a simple linear equation would suffice. The provided options suggest linear relationships, but without further context, we cannot confidently select one.
In physics and mathematics, any relationship between two variables can be represented by an equation. If the relationship is linear, the equation will be of the form y = mx + b. In this scenario, the rate of change (slope m) and the initial value (y-intercept b) would be determined by the specific situation being modeled, such as the rate at which water is filling a basin or the rate at which a tide is rising.