You have not provided the options, therefore, I cannot give you an exact answer.
However, I will try to help you with the concept.
<u>First, we need to make all units the same in the problem. I will convert all units to ml.</u>
We have:
amount of bleach = 15 ml
amount of water = 3.75 liters = 3.75 * 1000 = 3750 ml
<u>Now, we will get the ratio between bleach and water:</u>

<u>This ratio is fixed, therefore, to get the right choice:</u>
1- make all units the same
2- for each option, divide the amount of bleach by the amount of water.
The correct choice would be the one giving you

Hope this helps :)