Consumer magazine: Because front-loading washers use less water than top-loading washers, ordinary powder detergent does not dissolve readily in front-loading washers. So, to get clothes really clean in a front-loading machine you need to use a detergent formulated especially for front-loading washers, instead of ordinary powder detergent. Which one of the following is an assumption required by the argument in the consumer magazine? ['A laundry detergent does not get clothes really clean in a washer unless it dissolves readily in it.', 'A washing machine gets clothes really clean only with a laundry detergent specially formulated for that machine.', 'A laundry detergent formulated especially for front-loading washers dissolves more readily in them than it does in top-loading washers.', 'Washers that use more water get clothes cleaner than those that use less.']