Answer:
C. kilometer --> mile --> AU --> light-year
Step-by-step explanation:
Option C is the right because kilometer is the smallest unit in the given options. Mile is a greater unit than a kilometer and the Astronomical unit is greater than miles. The light-year is the largest one.
1 km = 0,621 miles
1 mile = 1,07578e-8 Astronomical unit (AU)
1 AU = 1,58125e-5 light year