**Core Concept**
The bivalent oral polio vaccine (bOPV) is a modified version of the traditional oral poliovirus vaccine (OPV). It contains two strains of poliovirus: one from the wild-type poliovirus and another from the attenuated poliovirus used in the traditional OPV. The bOPV is designed to provide immunity against two serotypes of poliovirus, thereby reducing the risk of vaccine-associated polio.

**Why the Correct Answer is Right**
The bOPV contains two strains of poliovirus: type 1 (mOPV1) and type 3 (mOPV3). These strains are chosen based on the global polio eradication efforts, where type 1 and type 3 are the most prevalent serotypes causing polio. The mOPV1 and mOPV3 strains are more attenuated than the traditional OPV strains, which reduces the risk of vaccine-associated polio.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not specify the exact strains of poliovirus contained in the bOPV. While type 1 and type 3 polioviruses are indeed contained in the bOPV, the option is too vague and does not provide any specific information.
* **Option B:** This option is incorrect because it suggests that the bOPV contains type 2 poliovirus, which is not the case. The bOPV is designed to provide immunity against type 1 and type 3 polioviruses, not type 2.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the bOPV is a type of OPV that contains two strains of poliovirus, and it's not a replacement for the traditional OPV, which contains three strains of poliovirus. The bOPV is used in areas where the risk of polio transmission is low, and it's an essential tool in the global effort to eradicate polio.

**Correct Answer: C. mOPV1 and mOPV3**