Preparation of partnership agreement in writing is:

Voluntary

The correct answer is option 2- Voluntary.

Partnership is the result of an agreement between two or more persons to do business and share its profits and losses. The agreement becomes the basis of relationship between the partners. It is not necessary that such agreement is in written form. An oral agreement is equally valid. But to avoid disputes, it is preferred that the partners have a written agreement. Hence, Option 2 is correct.