The correct answer to this question is the following.
Unfortunately, you did not attach information about source 2, so we do not know the content of it.
However, trying to help you we can comment on the following.
The correct statement is "The United States captured major cities in México."
The statement that best describes the military campaigns of the Mexican-American War is "The United States captured major cities in Mexico."
One of the major advantages for the United States during the actions of the Mexican-American War was that the US army was much better prepared and had better weapons. It was a matter of time for the US to capture Mexico City. The US troops landed in the important port of Veracruz and arrived in Mexico City to capture the Chapultepec Castle in September 1947.
When the United States won the war, México and the US signed the Treaty of Guadalupe Hidalgo on February 2, 1848. México agreed to cede the states of California, Nevada, Utah, New Mexico, and Arizona.