simple future or present continuous (with a future meaning)

I would be happy if you could help me!

she can’t meet us on Saturday. a) she’ll work b) she’s working

which one is correct? a o b? or both? if so, what’s the difference in the meaning?

thanks so much

patrizia

I’d say “she will be working on Saturday”. The answers you gave both seem a little bit off. Perhaps it you could give more context we could be more certain.

As Cerberus says, additional context would be useful, but as it stands:
She can’t meet us on Saturday as she’s working
is acceptable. In this form an end ‘then’ or ‘at that time’ is assumed.

dear Cerberus
thanks so much.
I can’t give more context because they are sentences in an English grammar book “Essential Grammar in use” (raymond murphy Cambridge University Press). Sometimes books are really misleading!

thanks for your answer.

patrizia

Dear Beesnees!

thanks so much!

patrizia

Yes, if you have to make a choice, pick “she’s working”. Perhaps the present continuous without explicit time maker was what put me off, as Bee suggested.