Which sentence below shows correct use of em dashes? (4 points)
Select one:
a. In a-thousand-years, most of our greatest monuments such as they are will have crumbled to nothing.
b. In a thousand years, most of our greatest monuments-such as they are-will have crumbled to nothing.
c. In a thousand years, most of our greatest - monuments such as - they are will have crumbled to nothing.
d. In a thousand years, most of our greatest monuments such as they are will have crumbled-to-nothing.