Answer: Use the Bilingual Evaluation Understudy (BLEU) score to estimate the relative translation quality of the two methods.

The correct answer is **B: Use the Bilingual Evaluation Understudy (BLEU) score to estimate the relative translation quality of the two methods.** **Reasoning:** 1. **BLEU Score is the Standard Metric for Machine Translation Evaluation:** BLEU is a widely accepted automatic evaluation metric specifically designed for machine translation tasks. It measures the similarity between machine-generated translations and human reference translations by calculating n-gram precision with a brevity penalty. 2. **BLEU is Best for Relative Comparisons:** The question describes a scenario where the company is comparing the translation tool's outputs against human translations on the same documents. BLEU scores are most effective for comparing the relative performance between different translation systems (e.g., System A vs. System B, or in this case, machine translation vs. human translation). It helps determine which method produces translations that are closer to the human references. 3. **Why Not Absolute Quality Estimation:** BLEU scores are not designed to provide absolute quality measurements (like "this translation is 85% accurate"). They are comparative metrics that work best when you have reference translations to compare against, which is exactly what the company has set up with their parallel data process. 4. **Why Not BERTScore:** While BERTScore uses contextual embeddings from models like BERT to measure semantic similarity and can be useful for translation evaluation, it is not the standard or most commonly used metric for machine translation benchmarking. BLEU remains the industry standard for automated translation evaluation due to its simplicity, interpretability, and widespread adoption in research and industry. 5. **Context-Specific Considerations:** For customer service translation tools, where accuracy and consistency are crucial, BLEU provides a reliable way to benchmark the tool's performance against human standards. The parallel data setup with human translations as references is ideal for BLEU scoring. Therefore, using BLEU to estimate relative translation quality between the tool and human translations is the most appropriate strategy for this evaluation scenario.

Author: LeetQuiz Editorial Team