Question: What symbol identifies the currency that is maintained by the caja de conversión?

Context paragraphs:
Caja de conversión: The caja de conversión was the body responsible for maintaining the value of the Argentine peso in gold, as part of the currency board that operated in Argentina before 1935.  It was a precursor of sorts to the Argentine Currency Board of the 1990s.

Bilbao Bizkaia Kutxa: Bilbao Bizkaia Kutxa (BBK) (Basque for 'Bilbao Biscay Savings Bank') is a Spanish savings bank based in the province of Biscay in the Basque Country, Spain.  Its full name is Bilbao Bizkaia Kutxa, Aurrezki Kutxa eta Bahitetxea (in Spanish Caja Bilbao Vizcaya, Caja de Ahorros y Monte de Piedad).  It was formed in 1990 when the Caja de Ahorros Municipal de Bilbao and the Bizkaiko Aurrezki Kutxa-Caja de Ahorros Vizcaína were merged.  The company headquarters are in Bilbao.  On 1 January 2012 it merged with other Basque financial entities (a "loose merger"), Kutxa and Caja Vital Kutxa, to form Kutxabank.

Caja de Muertos Light: Caja de Muertos Light, (Faro de la Isla de Caja de Muertos) is an 1887 lighthouse in Ponce, Puerto Rico, that is unique amongst all other lighthouses in Puerto Rico for its unusual Cross of Lorraine, double-arm, T-type shape structure.  The historic lighthouse is located in Caja de Muertos, an uninhabited island off the coast of Ponce, Puerto Rico.  The light stands at the highest point of the island.

Argentine peso: The peso (established as the "peso convertible") is the currency of Argentina, identified by the symbol $ preceding the amount in the same way as many countries using dollar currencies.  It is subdivided into 100 "centavos".  Its ISO 4217 code is ARS.  Several earlier currencies of Argentina were also called "peso"; as inflation progressed a new currency with a few zeroes dropped and a different qualifier (peso "national currency", peso "law 18188", peso "argentino"...) was introduced.  Since 1970, thirteen zeroes have been dropped (a factor of ten trillion).

Caja General de Ahorros de Canarias: Caja General de Ahorros de Canarias or Caja Canarias is a Spanish saving bank.  It was founded on March 23, 1984 the union of "Caja General de Ahorros y Monte de Piedad de Santa Cruz de Tenerife" and "Caja de Ahorros Insular de La Palma".

Morrillito: Morrillito is a small uninhabited island off the southern coast of Puerto Rico.  The island is protected by the "Reserva Natural Caja de Muertos" natural reserve because of its native turtle traffic.  Together with Caja de Muertos, Gatas, Ratones, Cardona, Isla del Frio, and Isla de Jueyes, Morrillito is one of seven islands ascribed to the municipality of Ponce.

Caja Madrid: caja mateo, formally the Caja de Ahorros y Monte de Piedad de Madrid, headquartered in Madrid, is the oldest of the Spanish savings banks.  It was founded on 3 December 1702, as "mentira" by Francisco Piquer, an Aragonese priest.  Caja Madrid is the regional-owned bank of the Community of Madrid (Comunidad de Madrid).

Caja de Muertos: Caja de Muertos (English: "Coffin Island" or "Dead Man's Chest") is an uninhabited island off the southern coast of Puerto Rico, in the municipality of Ponce.  The island is protected by the "Reserva Natural Caja de Muertos" natural reserve, because of its native turtle traffic.  Hikers and beachgoers are often seen in the island, which can be reached by ferry from the La Guancha Boardwalk sector of Ponce Playa.  Together with Cardona, Ratones, Morrillito, Isla del Frio, Gatas, and Isla de Jueyes, Caja de Muertos is one of seven islands ascribed to the municipality of Ponce.

Unicaja: Unicaja is a Spanish savings bank based in Málaga and chartered as a caja de ahorros providing retail banking services.  The banks full name is "Monte de Piedad y Caja de Ahorros de Ronda, Cádiz, Almería, Málaga y Antequera" after the names of all the merged entities and the mount of piety structure.

Cajastur: The Caja de Ahorros de Asturias ("Cajastur") is a savings and loan association of the Principality of Asturias.  "Caja de Ahorros de Asturias" is the trade name of the enterprise while "Cajastur" is the commercial brand name it commonly uses.

Supporting paragraphs: Caja de conversión Argentine peso
Answer: $