Final answer:
In alphabetic filing, cross-referencing is necessary for various reasons, including when a married woman uses her professional name, dealing with names that sound alike but are spelled differently, and when people use nicknames or variations of their names.
Step-by-step explanation:
In alphabetic filing, cross-referencing is necessary for several reasons. One reason is when a married woman prefers to use her professional name, which may be different from her legal name. For example, if a woman's legal name is Jane Smith, but she prefers to be known professionally as Jane Johnson, her file should be cross-referenced under both names.
Another reason for cross-referencing is when dealing with names that sound alike but are spelled differently. For instance, if there are two individuals named John Smith and Jon Smith, their files should be cross-referenced to avoid confusion.
Lastly, cross-referencing is necessary when people use nicknames or variations of their names. For example, if a person named James prefers to be called Jim, their file should be cross-referenced under both names.
Therefore, the correct answer is option d) all of the above.