What is the difference between open and closed code?

• A. Open code is unreadable; closed code is easy to read
• B. Open code requires deciphering; closed is easy to read
• C. Open code is easy to read, does not need to be deciphered; Closed code needs to be deciphered
• D. Open code always uses numbers; closed uses letters

Answer: (C)

The main idea is whether the information on the code is immediately readable or requires deciphering. Open codes present information in a way that anyone inspecting the product can read without needing a key or decoding steps. Closed codes are encoded or compressed and must be deciphered using a decoding method or table to interpret the actual data like date, lot, or facility. That makes open code easy to read and not needing deciphering, while closed code requires decoding to extract the real information. The other options mix up readability with the type of characters used, which isn’t what distinguishes open from closed codes.