The correct answer is A) banning gold-mining in California.
The issue that was not settled as part of the Treaty of Guadalupe Hidalgo was banning gold-mining in California.
The Mexican-American War was formally ended with the signing of the Treaty of Guadalupe Hidalgo on February 2, 1848. The war started on May 18, 1846, due to a dispute over the Texas territory. The American Army captured Mexico City on September 1947, and Mexico surrendered. Immediately, representants of both countries started to negotiate the peace agreements.
