The middle class I'm pretty sure
C or a because the colors are vivid and bright while its choice a
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 Sputnik launch changed everything. As a technical achievement, Sputnik caught the world's attention and the American public off-guard. Its size was more impressive than Vanguard's intended 3.5-pound payload. In addition, the public feared that the Soviets' ability to launch satellites also translated into the capability to launch ballistic missiles that could carry nuclear weapons from Europe to the U.S. Then the Soviets struck again; on November 3, Sputnik II was launched, carrying a much heavier payload, including a dog named Laika.
The Sputnik launch also led directly to the creation of National Aeronautics and Space Administration (NASA). In July 1958, Congress passed the National Aeronautics and Space Act (commonly called the "Space Act"), which created NASA as of October 1, 1958 from the National Advisory Committee for Aeronautics (NACA) and other government agencies."- https://history.nasa.gov/sputnik/
