The correct answer is - C. temperature.
By having the information about the average precipitation, and the temperature patters of a region, we can easily identify the climate type of the place. While this doesn't mean that the climate type can be identified in detail, it can be easily be put in one of the wider climatic types.
For example, if there are high temperatures throughout the whole year, and the precipitation is very low, than it is easy to predict that it is a tropical climate in question, more specifically, a desert. Or if there's medium amount of precipitation, and the climate varies a lot from the hottest to the coldest period of the year, it means that it is a temperate climate type in question.