In the length tension relationship of skeletal muscle, the length at which active tension is maximum is:

**Core Concept**
The length-tension relationship of skeletal muscle is a fundamental concept in physiology that describes how the force generated by a muscle contraction varies with the muscle's length. This relationship is crucial for understanding muscle function and movement.

**Why the Correct Answer is Right**
At optimal length, the overlap between actin and myosin filaments is optimal, allowing for maximum active tension generation. When a muscle is stretched beyond its optimal length (E), the actin and myosin filaments are over-extended, reducing the number of cross-bridges formed and thus the active tension. This is because the tropomyosin and troponin complex, which regulates muscle contraction, is unable to bind to the myosin heads effectively. As a result, the muscle generates less tension when stretched beyond its optimal length.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable as this option is not a point on the length-tension curve.
**Option B:** F is the point at which the muscle is maximally stretched and generates the least amount of tension, not the maximum.
**Option C:** D is not the correct answer as the muscle generates less tension when stretched beyond its optimal length, not at its optimal length.

**Clinical Pearl / High-Yield Fact**
The length-tension relationship is a key concept in understanding muscle physiology and is often tested in exams. Remember that the optimal length for maximum active tension generation is when the actin and myosin filaments are optimally overlapped.

**✓ Correct Answer: D. E**