Notice that the blue bar has 4 blocks while the green bar has 5 blocks.
Then, the ratio represented on the diagram is 4:5
Notice also that this ratio can be written in several different forms. Check each option to see if the ratio is equal to 4:5. To do so, write each ratio as a fraction in its simplest form:
12 to 15
3 to 4
Its already in its simplest form:
8 to 10
4 to 10
Therefore, the ratios that are equivalent to that in the diagram, are: