In each of the following situations, indicate whether the increase in net worth of the business is due to an owner investment, a revenue or a gain. a. The Workout Wear retail store sells athletic clothing. The owner, Paul Stretch, sold a sweatsuit to a customer on account. b. Marybeth Sourly operates a lemonade stand at the local high school football games. She bought a 50-pound bag of sugar for the business and paid for it out of her personal checking account. c. Samantha Courtland, a real estate attorney, performed legal services for a client, and the client signed a promissory note for the amount of the fee. d. The Milky Way dairy farm sold a delivery truck for an amount exceeding the book value of the truck