Correct Answer: To be in a risky situation

Solution : The third option is the correct answer.

The idiom to be on thin ice is a metaphor that implies being in a precarious or risky situation where there is a high likelihood of getting into trouble or facing adverse consequences. It suggests that one is treading on uncertain or fragile ground, similar to walking on thin ice that could break and lead to a challenging situation.

Therefore, the correct answer is: "To be in a risky situation."