Do let me know your availability? Jobs

[JobsJobs]

So I got called in for an interview. In the email she said she wants to have an informal chat.
And then it says'do let me know your availability from the beginning of September'

What does this mean ?

A) asking me when I could do the char in the beginning of September

B) asking me when I could start in the beginning of September?

If say the chat - September is only a week or so away, so she’s probs busy the next week and available after that to chat

Reply saying that you are available for the chat next week or beyond (specify dates e.g. not Monday for bank holiday), and that you would be looking to start work from X.