To find the size of the group after the changes, we can start with the initial number of members and adjust based on the changes:
- Initial group size: 10 members
- 4 females emigrate: 10 - 4 = 6 members
- 2 females immigrate: 6 + 2 = 8 members
- 2 gorillas are born: 8 + 2 = 10 members
- 1 male dies: 10 - 1 = 9 members
After applying all the changes, the final size of the group is 9.
So, the correct answer is 9.