Under the Bretton Woods system the following currencies were directly tied to gold: a. the British Pound
b. the US Dollar
c. the Thai baht
d. All of the above were directly tied to gold

Under the Bretton Woods system currencies which were directly tied to gold is the U.S Dollar. So, Option B is correct.

In July 1944, the Bretton Woods Agreement was signed. Delegates came from 44 different nations. The conference took place in Bretton Woods, New Hampshire. The Bretton Woods Agreement gained its name from this.

About The Bretton Woods:

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b. the US Dollar

Explanation:

The Bretton Woods Agreement was done in July 1944. It had delegates from 44 countries. The conference held in Bretton Woods, which is in New Hampshire. Hence it got the name, the Bretton Woods Agreement.

Under this system, gold was used as an exchange basis for the United States currency and the currency of other countries were pegged to the value of the dollar of the United States. The Bretton Woods System finally came to an end during the early 1970s as the President Richard M. Nixon made an announcement that their would be no more gold exchange for the US dollars.