What was "the crime of 1873" and what caused it?

The "Crime of 1873" was the notable omission of the standard silver dollar from the coinage law passed by Congress on February 12, 1873, and signed into law by President Ulysses S. Grant.1  This omission subsequently paved the way for the United States' adoption of the gold standard, which was highly controversial at the time, especially for those no longer able to turn their silver into legal tender.

answer; i do believe its (b) 12.5 years of age;