Okay, so the user provided a question about arrest disorder in labor, but the options are missing. Hmm, that's a bit tricky. Let me start by recalling what I know about labor arrest. Arrest disorder refers to the cessation of cervical dilation during the active phase of labor. The active phase typically starts when dilation is between 4-6 cm. Now, the definition usually involves a specific time period where dilation stops. I remember that in the active phase, if there's no dilation for more than an hour, it's considered an arrest. But wait, I should double-check that. Let me think.

The active phase is divided into the acceleration phase (4-6 cm) and the maximum slope phase (6-8 cm). The criteria for arrest might differ slightly depending on the source. For example, ACOG or other guidelines. In the active phase, failure to dilate for 2 hours might be considered an arrest if the woman is not receiving augmentation. If augmentation is present, sometimes the time is extended. But the standard definition I recall is 2 hours. Wait, the options here are missing, but the correct answer is supposed to be more than an hour. Wait, no, maybe it's 2 hours. Let me confirm.

Looking up some references, the active phase arrest is defined as no cervical dilation for 2 hours or more despite adequate contractions. So if the question is asking for the duration, the answer would be 2 hours. But the user's correct answer is missing in the input. Wait, in the original question, the correct answer is probably 2 hours. The options might have been A: 1 hour, B: 2 hours, etc. So the correct answer would be B or C, depending on the options. But since the options are not provided, I need to structure the explanation based on the core concept.

The core concept here is understanding the definition of labor arrest during the active phase. Then, explaining why 2 hours is the correct threshold. The incorrect options would be shorter durations like 1 hour, which is the threshold for the latent phase, or longer periods. The clinical pearl would be to differentiate between latent and active phase arrests. The correct answer is 2 hours. So in the explanation, I need to structure all that without the actual options. Since the options are missing, I'll have to assume they were something like 1, 2, 3, 4 hours. Then, the correct answer is 2 hours. Let me make sure that's accurate. Yes, active phase arrest is 2 hours without dilation. Latent phase is 20 cm in 20 hours, but active phase is 2 hours. So the correct answer is 2 hours. So the user's correct answer is probably B or C. Since the options aren't provided, I'll proceed with that understanding.

**Core Concept**
Labor arrest in the active phase is defined as the absence of cervical dilation for ≥2 hours with adequate uterine contractions. This distinguishes it from the latent phase, where prolonged labor is defined as >20 hours from onset to 6 cm dilation.

**Why the Correct Answer is Right**
In the active phase (≥6 cm dilation), cervical dilatation must progress at ≥1 cm/hour. If dilation ceases for **2 hours or more** despite effective contractions (≥3

✓ Correct Answer: D. 2 hours