To solve this problem, we must complete the sentence logically with the best available option.
The sentence given is: "To ensure success in a difficult task___________".
Now, let's analyze each option to determine which one best fits.
- "one needs to be persistent" suggests a requirement for an individual's persistence. However, it extends the phrase unnecessarily, making it less succinct.
- "persistence is needed" directly states the necessity of persistence, maintaining a concise and clear logical flow.
- "you need a person of persistence" implies the need for someone else to possess persistence, which diverges from a general guideline applicable to anyone facing a difficult task.
- "persistence is what one needs" is verbose and less direct in expressing the requirement.
Therefore, the option that completes the sentence logically and concisely is
"persistence is needed". This provides a direct, universally applicable statement affirming the necessity of being persistent to achieve success in challenging tasks.