Step 1: Understand Kant's and Coleridge's views on imagination.
Immanuel Kant, in his Critique of Pure Reason, emphasized that imagination is a key faculty that allows us to synthesize sensory data with conceptual understanding. For Kant, imagination bridges the gap between the world of appearances and the mind's understanding.
Samuel Taylor Coleridge, a Romantic poet and philosopher, also discussed imagination as a creative force that connects sensory experience with intellectual understanding, though he saw it as a more artistic and subjective process than Kant did.
Step 2: Analyze the other thinkers.
Plato’s view on imagination (or phantasia) was more focused on its connection to false beliefs or perceptions, rather than its role in uniting senses and concepts.
Horace was a poet and critic but did not engage in discussions regarding imagination in the context of Kantian or Coleridgean philosophy.
Thus, the correct answer is (C) and (D).