A student takes four samples of a white crystalline solid and places each in a well plate. On top of each sample, she carefully places 20 drops of clear mystery liquids A, B, C and D. Her results for each well are: Liquid A: The solid dissolves quickly. Liquid B: The solid appears unchanged. Liquid C: The solid floats on top of the liquid. Liquid D: Fizzing occurs and the solid disappears. Which combination of solid plus liquid indicates a chemical change has taken place? A) solid + liquid A B) solid + liquid B C) solid + liquid C D) solid + liquid D