Answer :
C. 2.6 cm³
1 cubic millimete = 0.001 cubic centimeter
2600 mm³ * 0.001 cm³/1mm³ = 2.6 cm³
OR
1 cubic centimeter = 1000 cubic millimeter
2600 mm³ * 1cm³/1000 mm³ = 2600 cm³ / 1000 = 2.6 cm³
1 cubic millimete = 0.001 cubic centimeter
2600 mm³ * 0.001 cm³/1mm³ = 2.6 cm³
OR
1 cubic centimeter = 1000 cubic millimeter
2600 mm³ * 1cm³/1000 mm³ = 2600 cm³ / 1000 = 2.6 cm³