Read the summary below. Choose the answer that BEST goes into the blank to complete the summary. The sun is a yellow dwarf star that lies in the center of our solar system, composed mainly of hydrogen and helium.

The energy produced in the sun's core provides almost all the heat and light necessary for life on Earth.
(A) The parts of the sun near the equator complete one rotation every 36 days.
(B) The sun is divided into several layers, with a dense core and a surface consisting of gas and plasma.
(C) The yellow dwarf star is one of several kinds of stars, but is the most common star in the Milky Way galaxy.
(D) Gravitational pull from the sun causes the matter in the sun to become more tightly packed, producing energy.