Answer:
c. Chemical weathering
Step-by-step explanation:
One of the famous landmarks in New York City is "The Statue of Liberty." It was built in 1886 as a gift to the Americans from France.
The statue is covered with copper sheets, thus, it used to have a brown color. However, over time, the color turned into greenish-blue. This is because the copper sheets underwent chemical weathering. Such process occurred as a result of the reaction of copper with Oxygen in the air and with water. It produced "copper carbonate," which is greenish-blue in color. Such color was noticeable in 1900, but it covered the entire statue in 1906.