The graph shown below illustrates the relationship between density and earthquake wave speed in different types of rock.A scientist detects an earthquake wave traveling at a speed of 6.5 km/s in rock with a density of 2.8 g/cubic cm. The scientists can BEST conclude that the wave is traveling through which type of rock?

Based on the graph, a density of 2.8 g/cubic cm corresponds to a wave speed of around 6.5 km/s. Therefore, the scientist can best conclude that the wave is traveling through granite rock.