Which word completes the sentence: '_______ response to your question about issue #123, we should be able to fix it by EOD.'

• A. On
• B. In
• C. With
• D. For

Answer: (B)

The main idea is using the fixed phrase "in response to" to introduce a reply. This collocation signals that what follows addresses a prior message or question, making the purpose of the note clear from the start. In this sentence, starting with "In response to your question about issue #123" sets up the rest of the statement as the answer and action plan, which is exactly what a professional email should convey. The comma after the introductory phrase correctly separates it from the main clause: "we should be able to fix it by EOD."

Other options don’t fit because they don’t form the natural, common connection needed here. Phrases like "on response to" or "with response to" sound awkward and are not used to begin replies. "For response to" also misleads the reader about the intent.