The correct answer is Length, mass, time.

The International System of Units (SI) is the modern form of the metric system. It is built upon a foundation of seven base units, which are independent and define all other units. While distance, speed, and acceleration are all important physical quantities, they are derived units, not base units. Similarly, temperature, pressure, and volume are also derived quantities. Force, power, and energy are derived from base units as well.

The seven base units in the SI system are:

• Length (meter, m): A measure of distance.
• Mass (kilogram, kg): A measure of inertia.
• Time (second, s): A measure of duration.
• Electric Current (ampere, A): A measure of the flow of electric charge.
• Thermodynamic Temperature (kelvin, K): A measure of temperature.
• Amount of Substance (mole, mol): A measure of the number of entities (atoms, molecules, etc.).
• Luminous Intensity (candela, cd): A measure of light power.

Option 2, Length, mass, and time, represents three of the fundamental base units upon which the SI system is built. All other units are derived from these base units and others.