For question a. both options measure the correct thing, however, it is unreal to think that Linda could use only 20 milliliters to wash her car. Therefore, the correct answer is liters
For question b., same as with question a., all options measure the correct thing, distance, but it is unreal to think that a mountain is only 3 millimeters, centimeters, or meters high. Therefore, the correct answer is kilometers.
For question c., same as the last two questions, both options measure the correct thing, mass. However, it is unreal to think that a dog weights only 6 grams, therefore, the correct option is kilograms
