Question: Searpion of Egypt joined the Coptic Orthodox Church which is based where?

Context paragraphs:
St. Mark Coptic Orthodox Church (Los Angeles): St Mark Coptic Orthodox Church (Coptic: // transliteration: "ti.eklyseya en.remenkimi en.orthodoxos ente fi.ethowab Markos") is a Coptic Orthodox church in Los Angeles and is one of the oldest Coptic parishes established in the United States.  It is one of over 200 Coptic Orthodox churches in the US.

St. Mary's Coptic Orthodox Church Massarra: St. Mary's Coptic Orthodox Church Massarra is a Coptic Orthodox church located in Shubra District, Cairo, Egypt.  It was built during the time when Pope Cyril V of Alexandria was Pope of the Coptic Orthodox Church and inaugurated in 1924.

Church of Saint Menas (Cairo): The Coptic Orthodox Church of Saint Menas (Egyptian Arabic: كنيسة مارمينا‎ ‎ "kenīset Mar-Mīna  ") is a Coptic Orthodox church near Coptic Cairo and is one of the oldest Coptic churches in Egypt, dating back to the sixth century.

St. Mary Coptic Orthodox Church (Los Angeles): Holy Virgin Mary Coptic Orthodox Church (Coptic: // transliteration: "ti.eklyseya en.remenkimi en.orthodoxos ente ti.parthenos ethowab Maria") is the second oldest Coptic Orthodox church that was established in Los Angeles and one of the largest Coptic parishes in California.  It is one of over 200 Coptic Orthodox Churches in the US.

Saint Mark's Coptic Orthodox Cathedral: St. Mark's Coptic Orthodox Cathedral is a Coptic church located in the Abbassia District in Cairo, Egypt.  The cathedral is the Seat of the Coptic Orthodox Pope.  It was built during the time when Pope Cyril VI of Alexandria was Pope of the Coptic Orthodox Church, and was inaugurated by him in 1969.

Coptic Orthodox Church in Malaysia: The Coptic Orthodox Church in Malaysia is an Oriental Orthodox Christian church in Malaysia.  It comes under the episcopal jurisdiction of the Coptic Orthodox Diocese of Sydney and its Affiliated Regions, a diocese of the Coptic Orthodox Church of Alexandria.

Coptic Orthodox Church of Alexandria: The Coptic Orthodox Church of Alexandria is an Oriental Orthodox Christian church based in Egypt, Northeast Africa and the Middle East.  The head of the Church and the See of Alexandria is the Patriarch of Alexandria on the Holy See of Saint Mark, who also carries the title of Coptic Pope.  The See of Alexandria is titular, and today the Coptic Pope presides from Saint Mark's Coptic Orthodox Cathedral in the Abbassia District in Cairo.  With 18–22 million members worldwide, whereof about 20 million are in Egypt (see Demographics section below), it is the country's largest Christian church.

Serapion of Egypt: Father Serapion was born in the year 1709 by the name Girgis Henein Abdel-Messeih.  He join the monastery of the Coptic Orthodox Church at the age of twenty-six years old in the year 1735 and given the monasticism name Serapion.  Father Serapion returned to his monastery in the year 1903 after he disappeared for over 150 years.  In less than a month after his return he departed in peace at the age of 194 years old.

Coptic Orthodox Church in Mexico: Decades later, Mexico had a growing Coptic Orthodox community of its own, as it was less than one decade ago when some Coptic families settled in Mexico.  The first Coptic Orthodox church in Mexico is St. Mary and St. Mark's Coptic Orthodox Church in Tlaycapan, Mexico.  It was founded in 2001 and measures about 2000 square meters.  The current priest is Father Zakaria Al Bramousy.

St. Takla Haymanot's Church (Alexandria): St. Takla Haymanot's Church is a Coptic Orthodox church in the city of Alexandria, Egypt, located in the district of Ibrahimia near Alexandria Sporting Club.  Consecrated on 19 June 1969, it is dedicated to the 13th century Ethiopian Orthodox monk Saint Tekle Haymanot.  It was visited by Ethiopian patriarch Abune Paulos on 15 July 2007 as part of his landmark trip to Egypt aimed at repairing ties between the Ethiopian Orthodox Tewahedo Church and the Coptic Orthodox Church of Alexandria.  All the pictures and icons in St. Takla Haymanot's Church are the work of famed Egyptian artist Isaac Fanous.  The church maintains one of the best Coptic-related websites on the Internet.

Supporting paragraphs: Serapion of Egypt Coptic Orthodox Church of Alexandria
Answer: Egypt, Northeast Africa and the Middle East