Why should you always enclose your `grep` search pattern in single quotes? (e.g. `grep -v '\?*' file` as opposed to `grep -v \?* file`)

		They are required by `grep`.
		Some shell metacharacters are also regular expression characters, so `grep` could get confused when interpreting the command string. Quoting them makes `grep` ignore them and pass the literal characters to `bash`.
		Some regular expression characters are also shell metacharacters and `bash` could get confused when interpreting the command string. Quoting them makes `bash` ignore them and pass the literal characters to `grep`
		They are required by `bash`.