The correct option is option C ("A room of their own").
In "Shakespeare's Sister", Virginia Woolf creates the imaginary figure of a hypotetical sister for Shakespeare in order to contrast what it would take for a woman to realize herself as a writer as opposed to a male.
The number one thing a woman writer will need would be money. If she's able to rely only on herself to earn her living, she'll get to determine freely what she does with her spare time. Also, with a room of her own she'll also be free to form her own opinions without the imposition or influence of anyone else holding her down.
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