**Core Concept:** Abdominal pain and vaginal bleeding are common presentations in gynecological emergencies, and can be indicative of conditions like ectopic pregnancy or ruptured ovarian cyst.

**Why the Correct Answer is Right:**

Option A (Investigate for ectopic pregnancy) is the correct answer because the patient's symptoms combined with her history suggest a potential gynecological emergency. The patient's presentation of sudden onset right lower abdominal pain, vaginal bleeding, and elevated blood pressure (hypertension) with low pulse rate (bradycardia) are crucial clues pointing towards ectopic pregnancy, which is a life-threatening condition.

**Why Each Wrong Option is Incorrect:**

Option B (Investigate for appendicitis) is incorrect because the patient's history and clinical examination findings are more consistent with an ectopic pregnancy than appendicitis. Appendicitis usually presents with pain that starts in the right lower quadrant and migrates to the right iliac fossa.

Option C (Investigate for ovarian torsion) is incorrect as the patient's history and clinical examination findings do not suggest torsion of an ovary. Torsion usually presents with acute onset severe pain, often with nausea, vomiting, and a high-pitched scream.

Option D (Investigate for endometriosis) is incorrect because the patient's history and clinical examination findings are more consistent with ectopic pregnancy. Endometriosis usually presents with chronic pain, not sudden onset pain and bleeding.

**Clinical Pearl:** In suspected cases of ectopic pregnancy, prompt assessment and intervention are crucial as it is a potentially life-threatening condition. Assessing her for ectopic pregnancy is essential, given her risk factors and clinical presentation.

**Correct Answer:** A. Investigate for ectopic pregnancy.