Which of the following sets include only like terms? Choose all answers that are correct. A. {18f g, - 1.93f g, -56f g, 1/22fg} B. {5.27q, -8.19q, -15q, 2/7q} C. {21.3st, -100st, 9.06st, 7/9st} D. {-1wxy, 276wxy, 4.38wxy, 4 7/15wxy}