**Core Concept**
The OPV Bivalent vaccine is a type of oral poliovirus vaccine that contains a combination of two different strains of poliovirus, which are used to provide immunity against poliomyelitis. This vaccine is designed to prevent the spread of poliovirus and ultimately eradicate the disease.

**Why the Correct Answer is Right**
The OPV Bivalent vaccine contains two strains of poliovirus: Poliovirus type 1 (PV1) and Poliovirus type 3 (PV3). These strains are selected based on the global epidemiology of poliovirus and are used to provide broad protection against the most common strains of the virus. The inclusion of PV1 and PV3 in the Bivalent vaccine is crucial in preventing the spread of poliovirus and achieving global eradication. The use of two strains in the vaccine ensures that it can provide effective immunity against a wider range of poliovirus strains, thereby increasing its effectiveness in preventing poliomyelitis.

**Why Each Wrong Option is Incorrect**
**Option A:** P1 & P2 - This option is incorrect because the OPV Bivalent vaccine does not contain Poliovirus type 2 (PV2). PV2 was declared eradicated in 2015, and it is no longer included in the vaccine.

**Option C:** P2 & P3 - This option is incorrect because the OPV Bivalent vaccine does not contain Poliovirus type 2 (PV2), as mentioned earlier. The vaccine contains PV1 and PV3, not PV2 and PV3.

**Option D:** P1, P2 & P3 - This option is incorrect because the OPV Bivalent vaccine only contains two strains of poliovirus, PV1 and PV3. PV2 is not included in the vaccine.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the OPV Bivalent vaccine is designed to provide broad protection against poliovirus, but it does not provide immunity against all strains of the virus. Therefore, it's crucial to maintain a high level of vigilance in detecting and responding to poliovirus outbreaks, especially in areas where the virus is still present.

✓ Correct Answer: B. PI & P3