Consider the two prompts below designed for a large language model:

Prompt A: Classify the sentiment of the following movie review as 'positive', 'negative', or 'neutral'. Review: [Movie Review Text]

Prompt B: `You are an AI assistant for a new tech startup. Your task is to categorize customer feedback into one of three custom labels: 'Feature Request', 'Bug Report', or 'Usability Issue'.

• 'Feature Request' suggests a new capability.
• 'Bug Report' describes something that is broken or not working as intended.
• 'Usability Issue' describes a part of the product that is confusing or difficult to use. Feedback: [Customer Feedback Text]`

Explain why Prompt B must include significantly more detail than Prompt A to achieve a reliable and accurate classification from the model.