Question

In the oral tradition, each telling or singing of a story differed from the last.

Answer 1

Yes, the answer is definitely A - true. In the oral tradition, obviously, people didn't use written texts, they told their tales from memory. And of course they would add something, or remove something else, or use a different vocabulary from the person who told them that story. It cannot be told in the exact same way the previous person told it, it is impossible.