This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to clean fake tanner from white sheets
Create a mixture of hot water and biological laundry detergent.
It is best to use a bathtub for this as it is large enough to hold the sheets in and won't overflow. Once the bathtub is filled with hot water, add a small cup of biological washing powder and stir well with a large spoon or stirrer to create the cleaning mixture.

pick from the following.
I. Keep in mind you should rinse the stains you want out if you don't remove them with the hottest water you can manage. Soften the sheet before applying the cleaning solution.;
II. Mix the dry ingredients together into the bathwater. Don't over mix this, as the dry ingredients will react violently with each other, which will cause your washed sheets to stick together.;
III. Alternatively, you can use a few drops of an enzyme scrub to help treat tanner stains. Lemon juice also works well, since it has antibacterial and anti-inflammatory properties.;
IV. Biological detergent has enzymes in the powder that help clean stains that non-biological detergent does not contain. Place the sheets into the cleaning mixture.;
The answer is:
IV.