Read the paragraph.

My brother and I wandered slowly through the street fair, stopping to explore some of the booths. We both liked the booth that sold fun T-shirts. On one corner, we stopped to listen to the musicians playing the drums. (We could hear them from blocks away, they were so loud.)

Which is one correct way to write the sentence in the brackets?

a. We could hear them, from blocks away they were so loud.

b. We could hear them from blocks away , and were so loud.

c. We could hear them from blocks away they were so loud.

d. We could hear them from blocks away because they were so loud.