You are playing the Regex Pattern Matcher game against o3-mini - (low).

Game history:
Turn 1: gpt-4o proposed text with target items: ["contact-us@domain.com","admin@site.edu.co","user.name@sub-domain.net","2023/10/09","09-10-2023","10.09.2023","&amp;","&#169;","&lt;","&notambiguous;","A-123-B","CD-456-78"]
o3-mini - (low) provided pattern: ^(?:contact-us@domain\.com|admin@site\.edu\.co|user\.name@sub-domain\.net|2023/10/09|09-10-2023|10\.09\.2023|&amp;|&#169;|&lt;|&notambiguous;|A-123-B|CD-456-78)$ (SUCCESS)

Turn 2: o3-mini - (low) proposed text with target items: ["a_b-c.X9@sub.domain.com","987-654-3210","2023/10/09 14:55","ID-A1B2C3-XYZ","2023-12-31","&special_entity_&#9731;"]
Current turn: 2 of 10
You are the SOLVER.

Your opponent has provided the following challenge:

Text: "Welcome to the ultimate regex challenge! Our key targets are buried within this mess. First, reach out at a_b-c.X9@sub.domain.com to connect. If you need urgent assistance, dial 987-654-3210 immediately. Remember to mark the event on 2023/10/09 14:55, and don’t forget our confidential identifier ID-A1B2C3-XYZ. Also, circle the new holiday on 2023-12-31. Finally, note the unique marker &special_entity_&#9731; amidst other decoys like &notvalid; and &fake_entity; that are just distractions."

You need to create a regular expression pattern that matches EXACTLY these items in the text:
[
  "a_b-c.X9@sub.domain.com",
  "987-654-3210",
  "2023/10/09 14:55",
  "ID-A1B2C3-XYZ",
  "2023-12-31",
  "&special_entity_&#9731;"
]

Rules:
1. Your regex must match ALL of the target items in the text.
2. Your regex must NOT match anything else in the text.
3. The pattern should be a valid JavaScript regular expression.
4. Do not include the leading and trailing slashes or flags in your pattern.

You'll use the "make_move" function to submit your solution with:
1. reasoning: Your reasoning for this regex pattern
2. move: The regex pattern as a simple string

Example of what the function parameters should include:
- reasoning: "This pattern matches email addresses by using..."
- move: "[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}"

IMPORTANT:
- The regex pattern should be a simple string.
- Do NOT use raw regex notation with slashes like /pattern/.
- Do NOT escape characters unless they need to be escaped in the regex itself.
- For example, to match parentheses, use "\(\)" not "\\(\\)".
- When your pattern contains backslashes, each backslash itself in the string should be a single backslash, not doubled.

Think carefully and test your pattern mentally before submitting.