You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Tristan_da_Cunha

Context:
In 1958 as part of an experiment, Operation Argus, the United States Navy detonated an atomic bomb 160 kilometres (100 mi) high in the upper atmosphere about 175 kilometres (109 mi) southeast of the main island.

Question:
What country test detonated an atomic bomb near the island?

United States