Read this paragraph from The Dark Game.

It may seem surprising that no Confederate sympathizers took action against Van Lew, given her strong and public views on secession and slavery. Surely there were suspicions, especially among her upper-crust neighbors, but the matter never went beyond those suspicions. Historians have suggested that the secessionists were victims of their own cultural bias, believing that no aristocratic person, and certainly not a lady, would ever consider taking part in anything as impolite as spying. A true lady managed her servants, prepared parties and gatherings, and blindly supported her husband. Such attitudes worked in Van Lew's favor, diverting suspicion from her.

What central idea is implied in this paragraph?

Elizabeth Van Lew did not follow the rules society set forth for ladies of her time and social class.
Elizabeth Van Lew was a successful spy because society did not expect a lady to serve in that role.
Elizabeth Van Lew was able to disguise her spying activities because she kept her views about the war to herself.
Elizabeth Van Lew created for herself an untrue but believable cover story: she was a wealthy lady living in a fancy neighborhood.

The central idea implied in this paragraph is that Elizabeth Van Lew was able to successfully carry out her spying activities because society did not expect a lady of her social class to be involved in such activities. Her ability to divert suspicion from herself was due to the cultural bias that believed aristocratic individuals, especially women, would not engage in activities like spying.