The possessive form of the pronoun "who" is "whose".
Possessive forms of pronouns do not use an apostrophe, the pronoun itself is the possessive form.
The pronoun "whose" functions as an interrogative and a relativepronoun.
EXAMPLES
Whose job is cleaning the lunchroom? (interrogative use, introduces a question)
The one whose job it is to clean the lunchroom is posted on this schedule. (relative use, introduces a relative clause)
The possessive form of the singular noun husband is husband's.Example: My husband's job involves a lot of travel.
The possessive form of the singular noun person is person's.Example: A person's job does not necessarily define that person.
The possessive form of the singular noun senator is senator's.Example: I got the summer job as a senator's intern.
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
The singular possessive of "ant" is "ant's" and the plural possessive is "ants'".
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive pronouns are "my," "mine," "your," "yours," "his," "her," and "its."
The singular possessive of dish is dish's
The singular possessive is Martin's.
The singular possessive is fish's.
Grave's is the singular possessive.
The singular possessive form of "test" is "test's".