## Core Concept
The power of a lens is defined as the reciprocal of its focal length, measured in meters. It is expressed in diopters (D). The formula to calculate the power of a lens is (P = frac{1}{f}), where (P) is the power in diopters and (f) is the focal length in meters.

## Why the Correct Answer is Right
Given that the focal length (f = 0.75m), we can substitute this value into the formula to find the power: (P = frac{1}{0.75} = frac{4}{3} = 1.33) diopters. This matches option , which represents (1.33D).

## Why Each Wrong Option is Incorrect
- **Option A:** This option suggests a negative power, which would imply a diverging lens. However, the sign of the power isn't specified by the focal length alone without context on whether it's converging or diverging. The calculation directly gives a positive value, making this incorrect based on the given focal length being positive.
- **Option B:** This option suggests a power of (frac{3}{4} = 0.75D), which does not match our calculation.
- **Option D:** This option suggests a power of (0.75D), which seems to confuse the focal length with the power.

## Clinical Pearl / High-Yield Fact
A key point to remember is that lens power is inversely proportional to focal length. A longer focal length means less power, and a shorter focal length means more power. For example, a lens with a focal length of 1 meter has a power of 1 diopter.

## Correct Answer Line
**Correct Answer: .**