Okay, let's tackle this question. The patient is a lady with ovarian cancer in follow-up and a raised CA 125 level. The question is asking about the next step. First, I need to recall what CA 125 is. CA 125 is a tumor marker used in the management of ovarian cancer. Elevated levels can indicate recurrence or progression.

So, the core concept here is the role of CA 125 in monitoring ovarian cancer. The next step after an elevated CA 125 would be to confirm the recurrence. But how? Typically, if CA 125 is rising, especially in a patient with a history of ovarian cancer, the next step is imaging to check for any recurrent disease. The standard imaging for this is a CT scan of the abdomen and pelvis.

Wait, but sometimes they might do a PET scan? Or maybe an MRI? I think CT is more common for initial staging and follow-up. Also, if there are symptoms suggesting recurrence, imaging is the next step. So the correct answer would be to perform a CT scan. Let me check the options again. The options aren't listed here, but the correct answer is likely CT scan.

Now, the wrong options might include options like starting chemotherapy immediately, which is too early without confirmation, or maybe a different imaging modality. Another wrong option could be blood tests alone, which isn't sufficient. Also, maybe a gynecological exam, which is not as specific.

Clinical pearls: Remember that CA 125 can be elevated in other conditions like endometriosis or pelvic inflammatory disease, but in a known cancer patient, a rising CA 125 is a strong indicator of recurrence. The next step is always imaging to confirm before proceeding to treatment. So the correct answer here is CT scan.

**Core Concept**
CA-125 is a tumor marker used to monitor recurrence in ovarian cancer. A rising CA-125 level in a post-treatment patient raises suspicion for recurrent disease, necessitating confirmatory imaging.

**Why the Correct Answer is Right**
The next step is **CT scan of the abdomen and pelvis** to evaluate for recurrent ovarian cancer. CA-125 elevation alone is insufficient to confirm recurrence due to potential false positives (e.g., benign gynecological conditions). Imaging is critical to detect new masses, ascites, or lymphadenopathy before initiating salvage therapy.

**Why Each Wrong Option is Incorrect**
**Option A:** "Repeat CA-125 in 1 month" delays definitive evaluation and risks treatment delays.
**Option B:** "Pelvic ultrasound" lacks sensitivity for detecting early recurrent ovarian cancer.
**Option C:** "Initiate second-line chemotherapy" is premature without confirming recurrence via imaging.

**Clinical Pearl / High-Yield Fact**
**CA-125 > 35 U/mL** is suspicious for recurrence, but **imaging is mandatory** to confirm. Remember: "CA-125 is a marker, not a diagnosis"—always correlate with clinical and radiological findings.

**Correct Answer: C. CT scan of abdomen and pelvis**

✓ Correct Answer: B. PET