Question: Which city was formerly of Shazhou County, Gao'an or Zhangjiagang?

Context paragraphs:
Shahe, Gao County: Shahe () is a town in the northeast of Gao County, southeastern Sichuan Province in Southwest China, located 30 km southeast of the city of Yibin.  In 2009, it administered 26 villages.  It is the home of Shahe tofu (沙河豆腐), one of the better known food products of Southern Sichuan that is also tender and features brilliant colours and Shahe Salted Duck (沙河板鸭).

Gao County: Gao County or Gaoxian is a county of Sichuan Province, China.  It is under the administration of Yibin city.

Honolulu County, Hawaii: Honolulu County (officially known as the City and County of Honolulu, formerly Oahu County) is a consolidated city–county located in the U.S. state of Hawaii.  The city–county includes both the city of Honolulu (the state's capital and largest city) and the rest of the island of Oʻ ahu, as well as several minor outlying islands, including all of the Northwestern Hawaiian Islands (islands beyond Niihau) except Midway Atoll.

Gao'an: Gao'an () is a city in the province of Jiangxi, China.  It is a county-level city, under the jurisdiction of the prefecture-level city of Yichun.

Chief executive (Irish local government): In local government in the Republic of Ireland, the chief executive of a city or county is the senior permanent official of its local authority.  Whereas the county council and city council are elected officials who formulate policy, the chief executive is an appointed official who manages the implementation of policy. <ref name="County/City Manager"> </ref> The position was introduced in 1929–42 based on the American council–manager government model, and until 2014 the chief executive was styled the county manager or city manager.  Their salaries range from €132,511 to €189,301 per annum.  The County and City Management Association (formerly the County and City Managers' Association) is the professional association for chief executives, and it is affiliated to the International City/County Management Association (ICMA).

Old City (Shanghai): The Old City of Shanghai (; Shanghainese: "Zånhae Loh Senshian"), also formerly known as the Chinese city, is the traditional urban core of Shanghai, China.  Its boundary was formerly defined by a defensive wall.  The Old City was the county seat for the old county of Shanghai.  With the advent of foreign concessions in Shanghai, the Old City became just one part of Shanghai's urban core but continued for decades to be the seat of the Chinese authority in Shanghai.  Notable features include the City God Temple which is located in the center of the Old City and is connected to the Yuyuan Garden.  With the exception of two short sections, the walls were demolished in 1912, and a broad circular avenue built over the former wall and moat: the southern half was named the "Zhonghua Road" and the northern half the "Minguo Road" (together making up ""Zhonghua Minguo"", or "Republic of China" in Chinese).  (The northern half was renamed "Renmin Road" ("People's Road") in 1950 by the new Communist government of Shanghai).

Longmen, Anxi County: Longmen () is a town in southern Fujian province, People's Republic of China.  located more than 50 km north of the city of Xiamen.  It is under the administration and in the southwest of Anxi County 14 km to the northeast.  It is home to a population of around 3000, over 90% of whom are surnamed Gao.

Parsian County: Parsian County (Persian: شهرستان پارسیان‎ ‎ ) (formerly, Gavbandi County) is a county in Hormozgan Province in Iran.  The capital of the county is Gavbandi.  The name of this county (and city), has been changed to Parsian county and Parsian city in 2007.  At the 2006 census, the county's population was 37,369, in 7,972 families.  The county is divided into two districts: the Central District, and Kushk-e Nar District.  The county has one city: Parsian.

Zhangjiagang: Zhangjiagang (), formerly Shazhou County (沙洲县), is a county-level city under the administration of Suzhou, Jiangsu province, China.  With 1,246,762 inhabitants at the 2010 census, the city is now part of Jiangyn-Zhangjiagang-Jingjiang metropolitan area with 3,526,260 inhabitants.  Continued growth will encompass the Shanghai-Suzhou-Wuxi-Changzhou Metroplex.  It borders the prefecture-level cities of Taizhou and Nantong across the Yangtze River, as well as Wuxi to the west.

Karun County: Karun County (Persian: شهرستان کارون‎ ‎ ) is a county in Khuzestan Province in Iran.  The capital of the county is the city of Kut-e Abdollah.  At the 2006 census, the county's population was 108,482.  The county is subdivided into three districts: the Central District, and Soveyseh District.  The county has one city: Karun, formerly named Kut-e Abdollah.  The county was established on January 23, 2013.

Supporting paragraphs: Gao'an Zhangjiagang
Answer: Zhangjiagang