The United States' total cotton output tripled between 1816 and 1826. Cotton continued to rise in value as the nation's primary export, and by 1836, would make up two-thirds of all American exports in terms of value.
Steam engines allowed advancements in transportation and trade by powering locomotives and steamships that carried goods and people.
Steam engines were powerful and reliable. Therefore, they helped Britain expand its economy and engage in long-distance movement of people and products.
The answer is c and that comes from personal experience