Final answer:
Pillow lavas are oceanic crust formed from late-differentiated liquids and are composed of basaltic lava flows that have cooled rapidly underwater, giving them a rounded shape. The correct answer to the question is D. Pillow lavas.
Step-by-step explanation:
Pillow lavas are oceanic crust that forms from late-differentiated liquids. Pillow lavas are basaltic lava flows that erupt and cool rapidly on the seafloor, creating rounded, pillow-shaped structures. These formations indicate that the rock was formed underwater, as the rapid cooling of the lava by seawater results in this distinct shape. The oceanic crust is primarily composed of basalt, a type of igneous rock that is produced by the cooling of volcanic lava and is less dense than the mafic rocks typically found in the continental crust. Basalts make up most of Earth's oceanic crust and can also be found on other planets with extensive volcanic activity.
Answering the multiple-choice question, the correct option is D. Pillow lavas.