Identify the incorrect statements among the following:
$(a)$ In earthworm,a single male genital pore is present.
$(b)$ Setae help in locomotion of earthworm.
$(c)$ The muscular layer in the body wall of earthworm is made up of only circular muscles.
$(d)$ Typhlosole is a part of the intestine of earthworm.

(A, C) The incorrect statements are $(a)$ and $(c)$.
$\Rightarrow$ Correction for $(a)$: Earthworms possess one pair of male genital pores situated on the ventrolateral side of the $18^{th}$ segment.
$\Rightarrow$ Correction for $(c)$: The muscular layer in the body wall of an earthworm consists of an outer layer of circular muscles and an inner layer of longitudinal muscles.
$\Rightarrow$ Statements $(b)$ and $(d)$ are correct. Setae are indeed involved in locomotion,and the typhlosole is a characteristic internal fold of the intestine that increases the surface area for absorption.