**Core Concept**
The movement of the knee joint involves the interaction of the quadriceps and patellar tendons with the patella, which acts as a pulley system to change the direction of the quadriceps force. The tibial tuberosity, the insertion point of the patellar tendon, is a key anatomical structure in this system.

**Why the Correct Answer is Right**
When the knee is extended from a flexed position, the patella moves superiorly in the trochlear groove of the femur. As the patella moves upwards, the tibial tuberosity, which is attached to the patellar tendon, also moves superiorly in relation to the patella. This movement is due to the change in the direction of the quadriceps force as the knee extends.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the tibial tuberosity does not move inferiorly in relation to the patella during knee extension. The patella moves superiorly in the trochlear groove, and the tibial tuberosity follows it.
* **Option B:** This option is incorrect because the tibial tuberosity does not remain stationary in relation to the patella during knee extension. The patella and tibial tuberosity are connected by the patellar tendon, and both move together as the knee extends.
* **Option C:** This option is incorrect because the tibial tuberosity does not move medially in relation to the patella during knee extension. The patella and tibial tuberosity move together in the same direction as the knee extends.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the patellofemoral joint is a complex system that involves the interaction of multiple structures, including the quadriceps, patellar tendon, and patella. Understanding the movement of these structures during knee extension is crucial for diagnosing and treating patellofemoral disorders.

**Correct Answer: A. The tibial tuberosity moves superiorly in relation to the patella during knee extension.**