The correct answer is option a. true.
The fossil fuels, including coal and oil are present very deep inside the earth. In the carbon cycle, only fixation of atmospheric carbon dioxide in the organic material takes place. This cycle does not involve the recycling of the fossil fuels.
The burning of the fossil fuels directly release carbon dioxide and other carbon compound in the atmosphere, which was not involved in the cycle when it was present deep beneath the earth and ocean. Hence, the burning of fossil fuels increases the amount of carbon in the carbon cycle.
