Which topic sentence should be added to this body paragraph?

More than likely, fellow volunteers will have many common interests and ideals. After all, volunteers usually seek opportunities to use their time and talents for issues they care about, and this is often a good starting point for many friendships. As co-volunteers, hours will be spent together learning from one another and inspiring each other while working to achieve a common goal. Teaming up with others to solve community problems and making changes for the better, not surprisingly, often leads to long-lasting bonds.