There is a question/answer set that may need attention, unless I'm really having a memory lapse!
The question is...
Which sentence reaffirms the fact that he does know about it:
The answer choices are...
En cuanto lo sepa.
Sí yo lo supiera.
Sí que lo sé.
...with "Sí que lo sé" being marked as correct.
Again, unless I'm really forgetting something here... I think either the question should be...
"Which sentence reaffirms the fact that you do know about it:"
...OR the correct answer should be:
Sí que lo sabe.
If I am forgetting something here, I will be happily corrected/reminded!