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:
American_Broadcasting_Company

Context:
While its radio network was undergoing reconstruction, ABC found it difficult to avoid falling behind on the new medium of television. To ensure a space, in 1947, ABC submitted five applications for television station licenses, one for each market where it owned and operated a radio station (New York City, Los Angeles, Chicago, San Francisco and Detroit). These applications all requested for the stations to broadcast on VHF channel 7, as Frank Marx, then ABC's vice-president of engineering, thought that the low-band VHF frequencies (corresponding to channels 2 through 6) would be requisitioned from broadcasting use and reallocated for the U.S. Army.

Question:
Which channels did Frank Marx think would be requisitioned by the U.S. Army?

channels 2 through 6