I'd go with option B. Offering to mail the customer a user manual could be really helpful, especially if the incident was related to some product or service they're using.
Option C seems like the obvious choice here. Sending written confirmation of the incident closure is a great way to ensure the customer has a record of the resolution.
Claudio
8 days agoArlette
16 days agoLaquita
2 days agoCoral
4 days agoArgelia
18 days agoMichel
20 days agoDetra
21 days ago