The huge Chiddush is that if a woman chooses on her own that she wants to learn all of Torah then you are allowed to teach them. The Drishah’s Chiddush that they can learn whatever they want on their own is big enough.
I personally have never refused to answer a woman’s question (not Lema’aseh) because there is definitely whom to rely upon. However, I would not feel comfortable saying Lechatchilah that a woman can learn from someone.