The correct answer is E. a, b and c only because all three statements explain why prompt design is important when working with generative AI and language models. A prompt is the instruction, question, or context given to an AI system to guide its response. When the prompt is clear, specific, and well-structured, the model is more likely to produce useful, relevant, and accurate output. This supports statement A because well-defined prompts help create a successful and productive conversation.

Statement B is also correct because poorly-defined prompts can make the conversation less useful. If the prompt is vague, incomplete, or confusing, the model may produce broad, irrelevant, or low-quality responses. Statement C is correct because unclear prompts can also lead to misleading content, especially when the model fills in missing details or interprets the request incorrectly. Therefore, prompt quality directly affects response quality, usefulness, and reliability, making E the best answer.