What does '!' mean in a route pattern?

• A. Literal character
• B. End of pattern
• C. Variable length wildcard
• D. Optional digit

Answer: (C)

In route pattern matching, wildcards determine how digits are consumed. The exclamation mark acts as a variable-length wildcard: it stands for zero or more digits that can follow the fixed prefix. This lets a single pattern cover numbers of different lengths without listing every possibility. For example, a pattern like 9! would match numbers that start with 9, such as 9, 91, 9123, 9123456, and so on. It’s not a literal character, nor does it indicate the end of the pattern or represent a single optional digit. That’s why it’s the correct interpretation.