Yes, there are several mock tests available for practicing multiple-choice questions with single correct answers. Here are the details:

1. EduRev:
- EduRev is a popular educational platform that offers a wide range of mock tests for various competitive exams, including UPSC.
- They have a dedicated section for multiple-choice questions (MCQs) where you can find mock tests specifically designed to help you practice answering questions with single correct answers.
- The platform provides detailed explanations for each question, helping you understand the concepts better.

2. UPSC official website:
- The official website of the Union Public Service Commission (UPSC) itself provides mock tests for aspirants.
- These mock tests are designed to simulate the actual exam environment and help you get familiar with the question pattern and time management.
- The official website also provides answer keys and explanations for the mock tests, allowing you to assess your performance and identify areas of improvement.

3. Coaching institutes:
- Many coaching institutes that specialize in UPSC preparation offer mock tests as part of their study material.
- These mock tests are often designed by experienced faculty members who have a deep understanding of the exam pattern and syllabus.
- Coaching institutes may provide mock tests in both online and offline formats, allowing you to choose the mode that suits you best.
- Additionally, some coaching institutes may also offer personalized feedback and guidance based on your performance in the mock tests.

4. Mobile applications:
- There are several mobile applications available on both Android and iOS platforms that offer mock tests for UPSC preparation.
- These applications often have a vast question bank with multiple-choice questions and provide instant feedback on your answers.
- Some applications also offer features like daily quizzes, performance tracking, and revision notes to enhance your preparation.

Conclusion:
- Practicing mock tests with multiple-choice questions is an essential part of UPSC preparation.
- Platforms like EduRev, the official UPSC website, coaching institutes, and mobile applications provide various options for accessing mock tests.
- These mock tests not only help you practice answering single correct answer questions but also simulate the actual exam environment, allowing you to assess your performance and identify areas for improvement.