Yes, you can choose any language for writing the answers in the UPSC Law Optional subject. The UPSC allows candidates to opt for the language of their choice for the optional subjects, including Law. However, there are certain points to consider while selecting a language for writing the answers:

1. Proficiency: It is essential to choose a language in which you are proficient. The UPSC evaluates the quality of answers based on content, clarity, and coherence. If you are not well-versed in a particular language, it may hamper your ability to express your thoughts effectively.

2. Availability of Study Material: Ensure that there is ample study material available in the chosen language for the Law optional subject. It is crucial to have access to textbooks, reference books, and previous years' question papers in the language you have selected.

3. Medium of Examination: While you can write your answers in any language, it is important to note that the question paper for the UPSC mains examination is set in both English and Hindi. Therefore, if you opt for a language other than English or Hindi, you will need to translate the questions in your chosen language while attempting the paper.

4. Answer Writing Practice: Answer writing is a significant aspect of UPSC preparation. It is advisable to practice writing answers in the chosen language to become comfortable and proficient in expressing your thoughts effectively.

5. Evaluation and Accessibility: Ensure that the chosen language is widely understood and assessed by the evaluators. Also, consider the availability of experts, mentors, and peer groups who can provide feedback and guidance in the chosen language.

In conclusion, while you have the freedom to choose any language for writing answers in the UPSC Law Optional subject, it is important to consider your proficiency, availability of study material, medium of examination, answer writing practice, and evaluation accessibility. Make an informed decision based on these factors to maximize your chances of success in the UPSC examination.