It might not look good if you say something bad that goes against most people's ethics, so to look good you'd want to make sure everything you say lines up with the majoritys ideals
A makes the most scene, as it is the act of Lenny talking about soft objects to Curley’s Wife that leads to her eventually demise, which leads towards the climatic moment.
He gave her the diary because he thought it would be good for her to write her thoughts down while she was hiding.