What Does the Author Think About the Impact Mainstream Protestant

What does the author think about the impact mainstream Protestant churches will have in the United States over the next century?

A) He believes their voice will be vital, as it is currently growing
B) He believes their numbers and influence will continue to ebb
C) He believes they will dominate the conversation about same-sex unions not only in their churches but also in society as a whole
D) He believes the religious situation in the United States is so fluid that it is impossible to know