The correct answer is option 3: kinetic energy. Kinetic energy is the energy an object possesses due to its motion. In the context of gases, the kinetic theory of gases states that the average kinetic energy of gas molecules is directly proportional to temperature, regardless of the type of gas.

Let`s examine the other options to understand why they are not the correct answer:

Option 1: Speed. Although the speed of gas molecules may vary, it is not the same for all gases at a given temperature. Different gases will have different average speeds at the same temperature.

Option 2: Mass. The mass of gas molecules can vary depending on the type of gas. Different gases have different molecular masses, so this quantity is not the same for all gases at a given temperature.

Option 4: Momentum. Momentum is the product of an object`s mass and velocity. Similar to speed, the momentum of gas molecules can vary depending on the type of gas. Thus, it is not the same for all gases at a given temperature.

Therefore, option 3, kinetic energy, is the correct answer.