What expression would you enter to add a key/value pair (John Doe, Apr/20/1980) in a dictionary?

The correct answer involves using the appropriate syntax to add a key/value pair to a dictionary. In this case, "John Doe" serves as the key and "Apr/20/1980" as the corresponding value.

Dictionaries are collections of key-value pairs, where each key is unique. To add a new item to a dictionary, you typically follow the pattern of defining the key followed by its associated value. The accepted format for adding to a dictionary includes wrapping the key in quotes to denote it as a string, which is crucial for correctly recognizing it during insertion.

In option C, the expression specifies "John Doe" as the key (wrapped in quotation marks, ensuring it's treated as a string) and "Apr/20/1980" as the value, aligning perfectly with the required syntax for dictionary manipulation. This clearly establishes "John Doe" as a unique identifier under which the associated birth date is stored, thus following standard practices for dictionary usage.

The other options fail to correctly adhere to this syntax or structure, either by misplacing key-value pairs or using incorrect formatting, resulting in errors for adding entries to a dictionary.