Question

under the neutrality act of 1937, the us government allowed the sale of nonmilitary goods to nations at war as long as they kept it secret paid in cash used submarines

Explanation:

The Neutrality Act of 1937 allowed the US to sell non - military goods to warring nations on the condition that they paid in cash (the "cash - and - carry" provision). "Kept it secret" is not related to the act's terms, and "used submarines" is irrelevant to the sales condition. So the correct option is the one about paying in cash.

Answer:

paid in cash