Final answer:
The combination of units that expresses volume is represented as M, cm, km^3 (option c). These include cubic meters (m^3), cubic centimeters (cm^3), and cubic kilometers (km^3).
Step-by-step explanation:
The combination of units that expresses volume is M, cm, km3. Therefore, the correct option is c) M, cm, km3. In the SI (or metric) system, volume is typically measured in cubic meters (m3), which is a derived unit based on the meter. For example, 1 cubic meter (m3) equals the volume of a cube that is exactly 1 meter on all edges. Similarly, cubic centimeters (cm3) and cubic kilometers (km3) are also units of volume, describing cubes of 1 cm and 1 km on each edge, respectively.