The most viscous among the choices is D. Honey at room temperature.
Viscosities of liquids typically vary with temperature. The higher the temperature, the lower the viscosity. Among the choices, only motor oil and honey appear to be the most viscous. The clue that helps determined the answer are the words "hot" and "room temperature". Hot motor oil is less viscous, while honey at room temperature is more viscous. Even comparing their viscosities at room temperature, honey already has a higher viscosity than motor oil.
