The correct option is B Note an apparent inconsistency
Mr. Beebe sounds cynical (though he says he is not) of the fact that Lucy Honeychurch is someone who plays the piano beautifully and likes to live quietly. He believes that one these both qualities will 'mingle'. In the given context, it seems like Beebe believes that a person can not be both: good at music and like to live quietly. He thinks that it is reflects an inconsistency in Lucy's personality. Thus D is the best answer.