**Core Concept**
Unruptured tubal pregnancy, also known as an ectopic pregnancy, is a life-threatening condition where a fertilized egg implants outside the uterus, often in the fallopian tube. The treatment of choice depends on the stability of the patient, the location and size of the ectopic pregnancy, and the presence of any complications.

**Why the Correct Answer is Right**
In cases of unruptured tubal pregnancy with a high serum b-hCG titre (20001 IU/ml), surgical intervention is often the preferred treatment option. This is because the high b-hCG levels indicate a larger and more complex ectopic pregnancy, which may be at risk of rupture. The surgical approach allows for the removal of the ectopic pregnancy and any associated adhesions, reducing the risk of future complications.

**Why Each Wrong Option is Incorrect**
* **Option A:** Medical management with methotrexate may be considered for unruptured tubal pregnancies with low b-hCG levels (less than 5000 IU/ml) and stable patients. However, in this scenario, the high b-hCG titre and potential for rupture make surgical intervention a safer choice.
* **Option B:** Expectant management involves monitoring the patient with serial b-hCG levels and ultrasound, but this approach is not suitable for unruptured tubal pregnancies with high b-hCG levels, as it does not address the potential for rupture.
* **Option C:** This option is incomplete, and without the actual text, it is difficult to determine why it would be incorrect.

**Clinical Pearl / High-Yield Fact**
In cases of unruptured tubal pregnancy, the decision to proceed with surgical intervention should be based on the patient's clinical stability, b-hCG levels, and ultrasound findings. A high b-hCG titre (greater than 5000 IU/ml) and a visible ectopic mass on ultrasound are red flags for surgical intervention.

**Correct Answer:** C. Surgical intervention (salpingectomy or salpingostomy) is the treatment of choice for unruptured tubal pregnancy with a high serum b-hCG titre (20001 IU/ml).