**Core Concept**
Ectopic pregnancy is a life-threatening condition where a fertilized egg implants outside the uterus, often in the fallopian tube. Ultrasound (USG) is a crucial diagnostic tool for identifying ectopic pregnancies. Key features on USG include the presence of an adnexal mass, free fluid in the pelvis, and the absence of an intrauterine pregnancy.

**Why the Correct Answer is Right**
Since the correct answer is not provided, let's discuss the common USG features of ectopic pregnancy. An empty uterus, adnexal ring, and free fluid in the pelvis are typical signs. The adnexal ring represents the ectopic gestational sac surrounded by a hyperechogenic ring.

**Why Each Wrong Option is Incorrect**
**Option A:**
**Option B:**
**Option C:**
**Option D:**

Given the lack of specific options, it's challenging to provide detailed explanations for each. However, in general, any option that describes a common USG feature of ectopic pregnancy (e.g., adnexal mass, free fluid) would be incorrect as the "except" option.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that transvaginal USG is more sensitive than transabdominal USG for detecting ectopic pregnancies, especially in early stages. The presence of an intrauterine pregnancy essentially rules out an ectopic pregnancy, except in rare cases of heterotopic pregnancy.

**Correct Answer:**