What are the basic regular expression characters?

• A. ^ $ . * [ ]
• B. g
• C. ( ) { } | ? +
• D. Digits and letters

Answer: (A)

Regular expressions rely on metacharacters that carry special meaning beyond literal characters. The foundational ones include the caret for the start of a string, the dollar sign for the end, the dot which matches any single character, the asterisk indicating zero-or-more repetition of the preceding element, and the square brackets that define a character class. Together, these five provide the essential tools to anchor patterns, broaden matching, repeat, and specify acceptable sets of characters. Other symbols like grouping, alternation, or additional quantifiers are useful but represent more advanced constructs beyond this basic set, and letters or digits by themselves aren’t special regex characters.