Select the correct answer. Marissa is testing a hypothesis through experimentation. She believes that immersing ocean coral in carbonic acid will slow the coral’s growth. Which of these actions will prevent Marissa from introducing confounding variables into her experiment? A. She releases cement particles into a random number of the coral samples. B. She uses three different types of coral to establish her dependent variables. C. She treats the coral samples identically with varying levels of carbonic acid. D. She obtains her coral samples from coral reefs surrounding different continents.