The very last one: "I have no children by which... "
The answer is, "The princess's hard work and training paid off and she wooed all of the suitors at the ball."
The sentence should be: "The princess's hard work and training paid off; She wooed all of the suitors at the ball." or "The princess's hard work and training paid off. She wooed all of the suitors at the ball."
I think that it is Problem/solution
