Which of the following is NOT one of the three phases of labor?

The correct answer pertains to the phases of labor typically recognized in obstetrics. Labor is traditionally divided into three stages: the latent phase, the active phase, and the transition phase. The latent phase involves the onset of cervical changes and early contractions that progressively become more intense. The active phase signifies a more pronounced progression of cervical dilation and more regular contractions. Finally, the transition phase represents the intense and often challenging final part of the first stage, where the cervix dilates from about 8 to 10 centimeters.

The option labeled "Transitional," while it may sound similar to "transition," is not a recognized phase. Therefore, identifying "Transitional" as not being one of the three distinct phases of labor is correct. Understanding these stages is crucial for monitoring labor progress and providing appropriate support and intervention during the childbirth process.