Answer:
The correct option is;
B. Earth is currently experiencing a period of global warming
Explanation:
From the graph, we have;
1) From 1880 to 1900 the temperature anomaly (°C) averages a few degrees below the average surface temperature
2) The decrease below the average surface temperature is larger from 1900 to 1920
3) The surface temperature rises more steadily from below average to a little above average from 1920 to 1940
4) Between 1940 to 1980, the temperature hovers around the average surface temperature
5) The Earth's surface temperature is more or less steadily increasing from 1960 to present
Therefore, the Earth is experiencing a period of global warming