To calculate the cloud base, what formula is applied?

The formula to calculate the cloud base is derived from the relationship between temperature, dew point, and the height at which clouds form. When using the formula in option A, you take the difference between the temperature and the dew point (in degrees Fahrenheit), divide by 4.4, and then multiply by 1,000 to convert the result into feet. This is based on the empirical rule that, on average, for every 1°C difference between temperature and dew point, clouds typically form about 400 feet above the ground.

Since the calculation uses Fahrenheit, the 4.4 factor is integral because it represents the rate of temperature drop per 1,000 feet. Thus, the formula accurately provides an estimation of how high the base of the cloud will be based on the temperature and dew point spread, making it the appropriate choice for calculating cloud base altitude accurately.

The other options incorporate variations or incorrect methodologies that do not align with the recognized meteorological principles for determining cloud base altitude, leading them to not be valid for this specific calculation.