Question:  Agustín de Iturbide y Green was the adopted son of which Belgian princess?
Context: Doña Sabina de Iturbide y Huarte, Princess of Mexico (30 December 1810 in Valladolid (now Morelia), Michoacán – 15 July 1871, Philadelphia) was a Mexican princess during the short-lived First Mexican Empire and a member of the Imperial House of Iturbide.  She was the eldest daughter of Agustín de Iturbide and Ana María de Huarte y Muñiz.  She was given the title of Princess of Mexico when her father was elected as the Mexican Emperor.  She given the style of Highness, as the style of Imperial Highness was reserved for only the Prince Imperial of Mexico, the heir apparent to the throne.  This position was held by her brother Don Agustín Jerónimo de Iturbide y Huarte. Don Agustín de Iturbide y Green, Prince of Iturbide (2 April 1863, in Mexico City, Mexico – 3 March 1925, in Washington, D.C.) was the grandson of Agustín de Iturbide, the first emperor of independent Mexico, and his consort Empress Ana María.  He became the adopted son, along with his cousin Salvador de Itúrbide y de Marzán, of Mexico's only other royal heads of state—Emperor Maximilian I of Mexico and Empress Carlota of Mexico.  After the death of Emperor Maximilian in 1867, he became the Head of the Imperial House of Mexico, but he had no children.  His claims passed to Maria Josepha Sophia de Iturbide, the daughter of his cousin, Salvador. Don Salvador de Iturbide y Marzán, Prince of Iturbide (18 September 1849, Mexico City - 26 February 1895, Ajaccio, Corsica) was the grandson of Agustín de Iturbide, the first emperor of independent Mexico, and his consort Empress Ana María.  He became the adopted son, along with his cousin Agustín de Iturbide y Green, of Mexico's only other royal heads of state—Emperor Maximilian I and Empress Carlota of Mexico. Juana María de Iturbide y Huarte (10 March 1812 – 2 October 1828), Princess of Mexico, known as Sister Margarita of Jesus, was the third child of Agustín I of Mexico (Agustín de Iturbide) and Empress Ana María.  She died at a young age at the Georgetown Visitation Monastery in Washington, D.C.. The House of Iturbide (Spanish: "Casa de Iturbide" ) is the former Imperial House of Mexico.  It was founded by Don Agustín de Iturbide in 1822 when the newly-independent Mexican congress confirmed his title of Agustín I, Constitutional Emperor of Mexico.  He was baptized with the names of Saints Cosmas and Damian at the cathedral there. Declaration to the world, or notes for history ("Manifiesto al mundo o sean apuntes para la historia" ) is a document written by Agustín de Iturbide (1793-1824) after he had been deposed in March 1823 as emperor of Mexico, and made public on October 13, 1824 after his death.  This document reflected his views of himself and of his duties in the politics of his country.  It was found by chance between his shirt and girdle after his execution for treason on July 19, 1824 in Nuevo Santander, now in Tamaulipas state.  The stains on the document are the blood of Iturbide. Princess Charlotte of Belgium, more commonly known as Carlota of Mexico (7 June 1840 – 19 January 1927) was a Belgian princess who became Empress of Mexico as the wife of Maximilian I of Mexico. Pedro Celestino Negrete (May 14, 1777 – April 11, 1846) was a Spanish politician and military man who served as a member of the interim government of México after the abolition of the First Mexican Empire.  He fought alongside of Agustín de Iturbide in the royalist army during the Mexican War of Independence.  He was a close collaborator of Iturbide during the empire, and then pressured him to abdicate to the Mexican crown. Prince Salvador of Mexico, also named Salvador de Iturbide y Huarte (17 July 1820 – June 7, 1856) was the eighth child (and third son) of Agustín I of Mexico and Empress Ana Maria Huarte.  He was married in 1845 to "Doña" María del Rosario de Marzán y Guisasola.  His descendants, through his son Salvador de Iturbide y de Marzán, are the current pretenders to the Mexican Throne. The Palace of Iturbide (1779 to 1785) is a large palatial residence located in the historic center of Mexico City at Madero Street #17.  It was built by the Count of San Mateo Valparaíso as a wedding gift for his daughter.  It gained the name "“Palace of Iturbide”" because Agustín de Iturbide lived there and accepted the crown of the First Mexican Empire (as Agustin I) at the palace after independence from Spain.  Today, the restored building houses the Fomento Cultural Banamex; it has been renamed the Palacio de Cultura Banamex.
Answer: Carlota of Mexico