The correct answer is family and friends.
When people obtain their gender identity their family and friends are the groups that impact them the most.
A family is a primary group that has a direct relation with the individual since the beginning of his/her life. The grade of influence is huge. Friends are a secondary group of reference and they play an important role in many aspects of people's lives. That is why these groups are so important for individuals when they obtain their gender identity. They expect the support, love, and comprehension from family members and closest friends.