Why Is Earth's Continental Crust Lower in Density Than Seafloor

Why is Earth's continental crust lower in density than seafloor crust?

A) Continental crust is made from a low-density volcanic rock called basalt.
B) Continental crust comes from volcanoes while seafloor crust comes from geysers.
C) Continental crust is made as the lowest-density seafloor crust melts and erupts to the surface near subduction zones.
D) Continental crust comes from Earth's inner core while seafloor crust comes from the outer core.