Answer: a. Email
Step-by-step explanation:
According to the given situation, face to face communication is more relevant while working on the project with a team. This will prevent the miscommunication as one is likely to observe and judge the posture and body language of other as if one is making false statement the body language will tell and the conversation will be clear. The chances of development of confusion and doubts will be low.
The email conversation can be considered official and might be restricted to the norms of transmission of information. The language used in email may be authoritative and may be unfriendly for team mates. The chances of development of confusion and doubts will be more thus may lead miscommunication.