Final answer:
Too much knee flexion during stance leads to decreased stability as it makes the base of support too small relative to the body's center of gravity, compromising balance.
Step-by-step explanation:
If a student has too much knee flexion during stance, it leads to B) Decreased Stability. While some knee flexion can help lower the center of gravity and increase stability, an excessive amount will make the base of support too small relative to the body's center of gravity (cg). When the cg is no longer above this base, stability decreases. For example, a football player slightly bends their knees to prepare for a play, increasing stability by widening the base of support and lowering the cg. However, if the knees are flexed too much, it might hamper their ability to react quickly as their balance is compromised.