Think about what it means, in inequality symbols, for a number (the temperature) to be at least 40 and at most 55.

Place the smaller bound, the temperature expression, and the larger bound in order in a single inequality, using $\le$ signs to include the endpoints.

In Desmos, enter the equation y = 95 - 3x. Here, $x$ represents time $t$ in minutes, and $y$ is the temperature.

Enter the horizontal lines y = 40 and y = 55. These represent the lower and upper temperature bounds.

Look at where the line y = 95 - 3x lies between the two horizontal lines (including the intersection points). The corresponding $x$-values are the times when the temperature is between 40°C and 55°C, inclusive. Choose the compound inequality option that has the smaller bound (40), then the expression for temperature, then the larger bound (55), with $\le$ signs.

The liquid cools from $95^\circ\text{C}$ at a constant rate of $3^\circ\text{C}$ per minute.

After $t$ minutes, the total temperature drop is $3t$, so the temperature $T$ (in degrees Celsius) is

“Between 40°C and 55°C, inclusive” means the temperature can be 40 or more, but no more than 55.

In inequality form, using $T$ for the temperature, this is

Now replace $T$ with the expression for temperature, $95 - 3t$:

This compound inequality shows all values of $t$ for which the temperature is between $40^\circ\text{C}$ and $55^\circ\text{C}$, inclusive. Among the answer choices, this inequality is exactly choice D: $40 \le 95 - 3t \le 55$.