Okay, let's tackle this question. The user provided a question about a woman with infertility and bilateral cornual block on HSG. The next investigation step is needed. First, I need to recall what HSG (hysterosalpingogram) shows. Cornual block means the fallopian tubes are blocked near the uterus. So, the next step would be to confirm the diagnosis and maybe look for other causes of infertility.

The core concept here is understanding the management of tubal factor infertility. HSG is the initial test, but if it's inconclusive or if there's a block, further imaging or laparoscopic procedures might be needed. The correct answer is likely laparoscopy with chromopertubation. That allows direct visualization and assessment of tubal patency.

Why is laparoscopy the right choice? Because HSG might not always be accurate. Laparoscopy is the gold standard for evaluating tubal patency and can also check for endometriosis or adhesions. Chromopertubation uses dye to see if the dye passes through the tubes, confirming patency.

Now, the wrong options. Let's say the options are A. Ultrasound, B. Repeat HSG, C. Laparoscopy, D. Hysteroscopy. Then, A is incorrect because ultrasound can't assess tubal patency. B is not better than laparoscopy, which is more accurate. D, hysteroscopy only looks at the uterine cavity, not the tubes. So the correct answer is C.

**Core Concept**
The question assesses the diagnostic approach to tubal factor infertility. Bilateral cornual block on hysterosalpingogram (HSG) suggests proximal tubal occlusion, necessitating further evaluation to confirm patency and exclude pelvic pathology. Laparoscopy with chromopertubation is the gold standard for definitive diagnosis.

**Why the Correct Answer is Right**
Laparoscopy with chromopertubation directly visualizes the fallopian tubes and pelvic cavity, confirming tubal patency via dye spillage. It also identifies endometriosis, adhesions, or other pelvic pathology contributing to infertility. This procedure is both diagnostic and therapeutic, offering real-time assessment beyond HSG limitations.

**Why Each Wrong Option is Incorrect**
**Option A:** Ultrasound cannot assess tubal patency or cornual block.
**Option B:** Repeat HSG lacks precision in confirming proximal tubal occlusion and risks radiation exposure.
**Option D:** Hysteroscopy evaluates the uterine cavity but not the fallopian tubes.

**Clinical Pearl / High-Yield Fact**
Never rely solely on HSG for tubal assessment in infertility. Laparoscopy with chromopertubation remains the gold standard, especially when HSG results are equivocal or blockage is suspected.

**Correct Answer: C. Laparoscopy with chromopertubation**

✓ Correct Answer: D. Laparoscopy and Chromotubation