You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You are also given a question about the story that requires an understanding of the relationship described in the background paragraph and the story. You need to come up with an answer to the given question; the answer will be a span from either the question or the story. In order to correctly answer the given question, you need to understand the relationship mentioned in the background paragraph and should be able to use it to understand that in the story. Your answer can not consist of any word that is not mentioned in any of these: the background paragraph, the story, or the question. You can directly copy and paste a span from the story or the question while answering the given question.

Background Paragraph: They feed on living hosts. As parasites , fungi live in or on other organisms and get their nutrients from their host. Parasitic fungi use enzymes to break down living tissue, which may causes illness in the host. Disease-causing fungi are parasitic. Recall that parasitism is a type of symbiotic relationship between organisms of different species in which one, the parasite, benefits from a close association with the other, the host, which is harmed. 
Story: Two botanists had different interests, Mike studied only trees and flowers, while Chris was fascinated with studying fungi. 
Question: Which botanist learned less about a type of symbiotic relationship between organisms of different species?
Mike.

Background Paragraph: Parallel slowdown is a phenomenon in parallel computing where parallelization of a parallel algorithm beyond a certain point causes the program to run slower (take more time to run to completion).[1]

Parallel slowdown is typically the result of a communications bottleneck. As more processor nodes are added, each processing node spends progressively more time doing communication than useful processing. At some point, the communications overhead created by adding another processing node surpasses the increased processing power that node provides, and parallel slowdown occurs. 
Story: John landed a job as an IT manager. His boss asked him to figure out problems in two similar programs, program A and program B. John found program A having parallel slowdown, but program B does not have parallel slowdown. He has to weigh the merits of using these programs. 
Question: Which program is doing less useful processing, program A or program B?
program A.

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. 
Question: Which one had seen less greenhouse gas emissions, char C or char D?

char D.