**Core Concept**
The case described is an anorectal malformation, a congenital anomaly where the anus and rectum are either absent or abnormally formed. This condition requires prompt surgical intervention to establish a normal fecal pathway and prevent complications such as rectal obstruction and incontinence.

**Why the Correct Answer is Right**
In the case of an absent anal orifice, a transverse colostomy is the most appropriate initial management. This procedure involves creating an opening in the abdominal wall to divert the fecal stream from the rectum, thereby preventing obstruction and allowing for the growth of the rectal pouch. The transverse colostomy provides a temporary solution, allowing the infant to pass stool and preventing complications while the definitive surgical repair is planned. The creation of a transverse colostomy also facilitates the subsequent surgical repair of the anorectal malformation, such as posterior sagittal anorectoplasty.

**Why Each Wrong Option is Incorrect**
**Option B:** Conservative management is not appropriate for anorectal malformations, as it can lead to complications such as rectal obstruction and incontinence.

**Option C:** Posterior sagittal anorectoplasty is the definitive surgical repair for anorectal malformations, but it is not the initial management for a newborn with an absent anal orifice. The transverse colostomy provides a temporary solution before the definitive repair.

**Option D:** Perineal V-Y plasty is a surgical procedure used to repair anal stenosis or strictures, not anorectal malformations.

**Clinical Pearl / High-Yield Fact**
In cases of anorectal malformations, the type and severity of the anomaly can be correlated with the presence or absence of certain physical examination findings, such as a rectal pouch or a perineal fistula.

**✓ Correct Answer: A. Transverse colostomy**