Which is more electronegative? hydrogen, carbon, magnesium, oxygen

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

i'm assuming that it's c.) red bank..