Task: Question Generation
Input (English): Background Paragraph: Weather conditions include air temperature, humidity, wind speed and direction, and precipitation. Weather is temporary. People in many states have the joke, "if you don't like the weather, wait five minutes and it will change." One way to change the weather is to have a different air mass move over the region. Interactions between air masses bring about a lot of weather. For example, thunderstorms and tornadoes form along a front. A front is where air masses meet. Fronts can bring about blizzards, thunderstorms, tornadoes and other types of weather. Weather prediction is much better than it was in past years. This is due in part to information from satellites. Climate is the long-term average of weather. The climate of a location depends on its latitude, position relative to the atmospheric circulation cells, position on a continent, altitude, and position relative to mountains. Areas with roughly the same climate make up a climate zone. The organisms that live within a climate zone create a unique biome. Earth's climate has changed throughout the planet's history. Earth was frigid at the end of the Pleistocene ice age, but has been warming since then. Since the Industrial Revolution the pace of warming has increased. In the past few decades the rate has really intensified. This is related to greenhouse gas emissions, primary from fossil fuel burning. The destruction of forests also increasing warming. The effects of global warming are already being seen. Treaties and voluntary actions are needed to reduce emissions to lessen the amount of global warming that will take place in the future. 
Story: Rob always confuses the terms climate and weather. He found it's better to compare them if he needs to learn more about their characteristics. To make things easier, he labeled the weather of his city as char A. Then he labeled the climate of this city as char B. Once finished with learning their characteristics, Rob focused on climate change issues. For that, he labeled the climate of present time as char C and climate just before industrial revolution as char D.
Output (English): Which one denotes shorter time period, char A or char B?