**Core Concept**
The focal length of a lens is defined as the distance between the lens and the point where parallel light rays converge or appear to converge after passing through the lens. A lens with a power of 0.25 m is considered a diverging lens, which spreads out light rays.

**Why the Correct Answer is Right**
The focal length of a lens can be calculated using the lensmaker's equation, but in this case, we are given the power of the lens. The power of a lens is defined as the reciprocal of its focal length in meters. Therefore, if the power of the lens is 0.25 m, we can calculate its focal length by taking the reciprocal of the power. The correct answer is the focal length that is equivalent to a power of 0.25 m.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided, so we will not evaluate it.
**Option B:** This option is not provided, so we will not evaluate it.
**Option C:** This option is not provided, so we will not evaluate it.
**Option D:** This option is not provided, so we will not evaluate it.

**Clinical Pearl / High-Yield Fact**
When working with lenses, it's essential to remember that the power of a lens is the reciprocal of its focal length. This relationship can be used to calculate the focal length of a lens given its power, or vice versa.

**Correct Answer: . 25 m**