Advertisement: My five-year-old identical twins wear matching clothing. I washed two of their soiled matching shirts, one in my regular laundry detergent, and one in new WAVE laundry detergent. The shirt washed in WAVE came out cleaner than the other shirt, so WAVE cleans better than my regular laundry detergent. Which of the following is an assumption on which the argument in the advertisement above depends? ['Most pairs of young identical twins tend to wear matching clothing.', 'The shirt laundered in the regular laundry detergent was not significantly less clean than the other shirt before being laundered.', 'Clothes washed in WAVE laundry detergent will come out cleaner than clothes washed in any other brand of laundry detergent', 'A soiled shirt laundered on a regular basis in the same laundry detergent will come out equally clean each time it is laundered.']