Why was the statement "In God We Trust” chosen as a national motto?

a. to express a shared belief that everyone is created equally and has the right to life, liberty, and the pursuit of happiness
b. to reflect a long history of religious belief that lays the foundation for religious freedom in the United States
c. to declare that the Christian faith is the most important religion in the United States
d. to show that Americans believe that faith in God is more important than other beliefs that make up our national ethos