Why Do Most Women Need a Lubricant in Order to Engage

Why do most women need a lubricant in order to engage in anal sex comfortably?

A) Because women in general do not find anal sex arousing.
B) Because this woman in particular does not find anal sex arousing.
C) Because she has not yet learned how to relax her external sphincter.
D) Because the anal mucosa does not produce much lubrication.
E) Because her vagina is producing a below-average amount of lubrication.