Which of the following regular expression patterns make the terms "confidential data" case insensitive?

[confidential data] is a character set that would match any single character present within the brackets (c, o, n, f, i, d, e, n, t, i, a, l, space, d, a, t, a), not the entire phrase "confidential data" in a case-insensitive manner.

In regular expressions, the /pattern/i syntax is commonly used, especially in languages like JavaScript, Perl, and FortiGate's implementation, where the 'i' flag appended after the closing slash specifies a case-insensitive match for the preceding pattern.

The syntax i/confidential data/ places the 'i' flag incorrectly before the opening slash, which is not standard regular expression syntax for case insensitivity.

"confidential data" represents a literal string and does not incorporate any regular expression syntax or flag for case-insensitive matching.