The best answer is A. b-a-e-d-c.

This sequence logically arranges the sentences of the invitation:

1. b. "I hope you’re doing well!" - A friendly introduction.
2. a. "I’m writing to invite you to join our club, where we connect with foreign friends and practice new languages." - Explains the purpose of the message.
3. e. "I know you’re interested in learning French and don’t have any French-speaking friends yet—I’m in the same boat!" - Finds common ground with the recipient.
4. d. "By joining us, we can learn French together and make new friends along the way." - Offers a benefit of joining the club.
5. c. "I would love to have you as part of the group." - Expresses enthusiasm for the recipient's potential inclusion.