A primigravida at 40 weeks gestation is admitted in active labor. The fetus is in a left occiput anterior (LOA) position with progressive cervical dilation and fetal descent. Vaginal exam reveals a well-applied fetal head, and the labor is progressing without complications. Based on these findings, which maternal pelvic type is most likely contributing to this optimal labor pattern?

A. Platypelloid pelvis: This pelvic type is characterized by a flattened inlet with a short anteroposterior diameter and a wide transverse diameter. These dimensions often lead to difficulty with fetal engagement and descent, increasing the likelihood of labor dystocia and the need for operative intervention. B. Gynecoid pelvis: The gynecoid pelvis has a rounded inlet, wide cavity, and evenly proportioned diameters, allowing the fetal head to engage and rotate efficiently. It supports smooth labor progress, especially in a left occiput anterior position, which aligns well with this pelvic shape for spontaneous vaginal delivery. C. Anthropoid pelvis: This pelvis is elongated anteroposteriorly and narrower transversely, predisposing the fetus to enter the pelvis in an occiput posterior position. Although vaginal birth can occur, it may be accompanied by prolonged labor or back pain due to fetal malrotation. D. Android pelvis: The android pelvis resembles a male pelvis, with a heart-shaped inlet and narrow dimensions. These features can lead to poor fetal head engagement, deep transverse arrest, and increased need for cesarean or assisted delivery due to ineffective fetal descent.