CHEYENNEPRETTY327GO CHEYENNEPRETTY327GO Mathematics Answered Which expression is the sum of -5.3m + 3.4n and 2.5n + 2.8m? A. -2.8m + 6.2n B. -2.5m + 5.9n C.-8.1m + 0.9n D. 2.5m + 5.9n + B