Answer:
Option B
Step-by-step explanation:
Option A is incorrect because the temperature has risen continuously from 1880 to 2000. However, this rise in temperature has been very marginal numerically thus option D is also incorrect. Option c is incorrect because in the graph temperature has risen in 2000 instead of dropping.
Over all the temperature of surface of earth has increased from near to minus 0.2 degrees in 1880 to near to 0.6 degrees in 2000. The temperature has increased by nearly 0.8 degrees. Thus, it can be said that the average surface temperature of earth has increased by 1 degree.