Which sentence has a clear transition between two ideas?

Question

Mowgli knows what needs to be done and is afraid to leave his family.
Mowgli is afraid to leave his family, but he knows what needs to be done.
Mowgli is afraid to leave his family. He knows what needs to be done.

Answer 1

The sentence with a clear transition between two ideas is:

Mowgli is afraid to leave his family, but he knows what needs to be done.

This sentence clearly indicates the contrast between Mowgli's fear and his understanding of what needs to be done, using "but" as a transition word.