The correct option is D Straight posterior part
Ascaris shows dimorphism, the female is longer and wider than the male. The tail is straight in female and carries a transverse anus and a chemoreceptor, called as amphid between the anus and the tip of the tail. In the male, the tail is curved and anus is replaced by cloaca from which the two equal chitinous spicules or penial setae project out.