premise: Princess Maria Gabriella of Savoy (Maria Gabriella Giuseppa Aldegonda Adelaide Ludovica Felicita Gennara; born 24 February 1940) is the middle daughter of Italy's last king, Umberto II, and Marie José of Belgium, the "May Queen", and a sister of the pretender to their father's throne, Vittorio Emanuele, Prince of Naples. She is an historical writer.
hypothesis: Princess Maria Gabriella of Savoy is the daughter of Umberto II.
reason: Princess Maria Gabriella of Savoy is the middle daughter of Umberto II and Maria Jose of Belgium.