The correct answer to this question is option 3: "To be too old to do things."

To be "over the hill" is an idiomatic expression that means someone is past their prime or too old to do things that they used to be able to do. It suggests that the person is no longer as capable or active as they once were.

Option 1, "To be on a mountain top," does not match the meaning of the idiom. It refers to a physical location rather than the age-related concept expressed by the idiom.

Option 2, "To travel in the jungle," is unrelated to the idiom and does not reflect its meaning.

Option 4, "To do something in the most complete way," also does not align with the intended meaning of the idiom. It suggests thoroughness or completeness rather than aging or diminished ability.

Therefore, the correct answer is option 3, "To be too old to do things." It accurately conveys the intended meaning of the idiom.