Look at the pendulum diagram. at which point is the kinetic energy of the pendulum the greatest

Position ' C ' is the middle of the swing.  That's where the weight is the lowest.

It's also the place where the weight is moving the fastest, so that means it's the place where the kinetic energy is greatest.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.