If the regular expression is "abc.de", which of the following will not match the regular expression?

Question

Options

• Aabcdde
• Babc.de
• Cabcde
• Dabc+de

• A
  4% (2)
• B
  9% (4)
• C
  71% (32)
• D
  16% (7)

Explanation

In regex, the . (dot) metacharacter matches any single character - it is not a literal period. The pattern abc.de therefore requires exactly one character (any character) between abc and de, making the full match six characters long. abcde (option C) is only five characters: after matching abc, the dot consumes d, leaving only e - which cannot satisfy the remaining de requirement, so it fails to match.

Why the distractors are wrong:

• A (abcdde) matches because . consumes the first d, leaving de to satisfy the tail.
• B (abc.de) matches because the literal . in the string satisfies the regex dot, which accepts any character including a period.
• D (abc+de) matches because + is just another character here - the regex dot happily consumes it.

Memory tip: Think of the regex dot as a "placeholder that demands exactly one character." If the string has zero characters where the dot stands (like C), the match collapses. Also remember: a dot in a regex is almost never a literal dot - to match a real period, you must escape it as \..

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