**Core Concept**
The hamstrings muscle group is a set of three muscles located at the back of the thigh: the biceps femoris, semitendinosus, and semimembranosus. These muscles play a crucial role in knee flexion and hip extension.

**Why the Correct Answer is Right**
The correct answer is one of the three muscles that make up the hamstrings muscle group. The biceps femoris is a two-joint muscle that has a long head and a short head, while the semitendinosus and semimembranosus are two-joint muscles that work together to flex the knee and extend the hip. The hamstrings muscles are innervated by the tibial nerve and receive blood supply from the popliteal artery.

**Why Each Wrong Option is Incorrect**
**Option A:** This muscle is actually part of the quadriceps muscle group, which is responsible for knee extension, not flexion.
**Option B:** This muscle is not a member of the hamstrings muscle group; it is actually a muscle of the thigh that is involved in hip flexion and knee extension.
**Option C:** This muscle is also not a member of the hamstrings muscle group; it is actually a muscle of the thigh that is involved in hip abduction and knee flexion.

**Clinical Pearl / High-Yield Fact**
The hamstrings muscles are commonly injured in sports that involve running, jumping, and quick changes of direction, such as soccer and basketball. Injuries to the hamstrings muscles can be painful and take several weeks to heal.

**Correct Answer:** C.