**Core Concept**
Taylor's Brace is a type of orthotic device used to treat and manage conditions affecting the foot and ankle. It is a rigid, three-posterior-spring carbon fiber or polypropylene orthosis designed to correct foot deformities and provide support.

**Why the Correct Answer is Right**
Taylor's Brace works by providing a stable and supportive environment for the foot and ankle. It helps to redistribute pressure, correct foot alignment, and prevent further deformity. The three posterior springs in the brace provide a push-off effect, assisting in the propulsion phase of gait. This is particularly useful in conditions such as equinus deformity, where the foot is abnormally plantarflexed.

**Why Each Wrong Option is Incorrect**
**Option A:** Taylor's Brace is not typically used for treating flat feet (pes planus), as it is not designed to correct the underlying arch structure.
**Option B:** While Taylor's Brace can provide support and stability, it is not primarily used for ankle sprains or strains, as it does not allow for the range of motion required for rehabilitation.
**Option C:** Taylor's Brace is not typically used for treating hammertoes, as it is not designed to correct the underlying deformity of the toe.

**Clinical Pearl / High-Yield Fact**
Taylor's Brace is often used in conjunction with physical therapy to help manage conditions affecting the foot and ankle. It is essential to consider the underlying cause of the deformity or condition when selecting an orthotic device.

**Correct Answer: D. Plantarflexion deformity of the foot (equinus)**