Question

If ______ rings me up, tell him that I’ll be in at 5.
A) Anything
B) Nobody
C) Everything
D) Something
E) Somebody

Answer 1

Hint: Indefinite pronouns are able to represent either countable nouns or uncountable nouns and also tells us about non-specific beings, objects, or places. They often have related forms across these categories: universal, assertive existential, elective existential, and negative.

Complete answer:
In the first option, Anything means a thing of any kind. Use it in questions and negative sentences. It can also be used to mean I don't mind.
In the second and third option, “Nobody" is an indefinite pronoun, meaning it does not tell about any particular person. It means the same thing as "no person" or "not anyone." As an indefinite pronoun that refers to an absence, "nobody" also has no defined amount. it becomes grammatically wrong if used with the sentence as it is not an existing entity
Nothing means no single thing. Used as subjects of a sentence or question. Everything means all the things. Similarly, nothing means non existing so it can also not be used and the sentence is referring to a single thing so everything cannot be used as well.
In the fourth option, Something that is unspecified or unknown and is used for an object which also does not fit in the sentence as an object cannot have human characteristics.
In fifth option, Someone and somebody are both pronouns that are used to refer to a person who is not known or specified. In most contexts, they are interchangeable.

Hence the correct option is E.

Note: Most indefinite pronouns are either singular or plural. However, some of them can be singular in one context and plural in another. The most common indefinite pronouns are listed below, with examples, as singular, plural or singular/plural.
Notice that a singular pronoun takes a singular verb and that any personal pronoun should also agree (in number and gender).