The literature is The Governess by Neil Simon.

What do you learn from these stage directions
in The Governess?
[The faintest trace of a smile her lips]
A. Julia is suddenly very happy.
B. Julia knows something Mistress doesn't
know.
C. Julia has made an important decision.
D. Julia is thinking about someone she loves.
Is the answer B?
Thank you :)

The answer is B, because Julia knows that no matter what, she will always stay the way she is, timid and so. She knows the mistress does not understand her outlook of the whole situation because of the difference in their social positions. The mistress thinks it's easy to speak up for yourself, because she is of upper class and whatever she voices out will be done. Meanwhile, Julia is a governess, not s servant nor of upper class, knows how hard it is to speak up for herself due to her lack of authority.

The answer is B

Reed, no worries, Andrew helped me.. thank you so much for all you do :)

Thank you so much Andrew! :D
I helped you with your science:)

in it

I don't know this play. B may well be the correct answer. To be sure, ask yourself, and reread the play to refresh your memory, if Julie does know something Mistress doesn't know. If Mistress is talking about something she doesn't know about yetand Julie does, then you're correct.

Thank you Reed! Here is the excerpt. Does my answer still make sense? Thank you again :)

I really don't know, from the excerpt you have posted. Again, look at what has happened BEFORE this exchange of dialog. What does Julia know? Is she plotting some way to assert herself that Mistress doesn't know about? Has she already done something that Mistress doesn't know about yet?

And I'm not sure what version of this story you are reading. Is this the Neil Simon play, also titled "The Good Doctor," or a 1990s British play of the same name? Or a film of the same name? There are several works called "The Governess."