When specifying criteria in the custom autofilter dialog box, use the wildcard to specify a single character.
a. ? b. *c. 'd. both a. and b.

Answer is option a. ?                                                    

Explanation:

Wild card also called wild character or wildcard character is a symbol that is used to replace or depict one or more characters. It is also used to locate specific item in data. It is sometimes used in file searches so that the full name does not need to be typed.

Examples of wildcard are

* specify one or more characters.[ ] matches characters with in the brackets.# matches or specifies single numeric character.- symbol specify range of characters (in ascending order).! symbol does not include the characters inside the brackets.

? wild card which shows a question mark (?) represents a single character. This symbol matches a single character in a certain position.

For example

t?ll matches tall, tell, and till. l?nd finds land and lend. l??d matches above example and also the following words like lord, loud, load, lard, lead, lied, laid, laud.

It should be by long pressing on the name of an answer if not i'm on a pretty old phone so it might be different for me

Ais your answer hope that