I can't seem to find this

First you must know the link 1dm∧3 = 1 liter
The volume of the cube is V=a∧3 = 1cm * 1cm * 1cm = 1 cm∧3
1dm∧3 = 1 dm * 1dm * 1dm = 10cm * 10cm * 10cm= 1000cm∧3 =>
1cm∧3= (1/1000)dm∧3 = (1/1000) liter
The correct answer is a.
Good luck!!!