Which best compares AC and DC?

a
AC flows in one direction, and DC repeatedly switches direction.
b
AC is used only in generators, and DC is used only in motors.
c
DC is used only in generators, and AC is used only in motors.
d
DC flows in one direction, and AC repeatedly switches direction.
Please Help me, I have no clue what I'm reading, and I'm trying to make a good grade on this formative assesement

What is the correct term for living the most sustainable life you can within your current circumstances?

Which of the following statements are incorrect?

•what conclusions can you make about the relationship between the volume of a gas and its temperature? • what conclusions can you make about the relationship between the volume of a gas and its pressure? • what possible variables have you not accounted for? as you did the procedures, is it possible that the atmospheric pressure may have changed? if it did change over the course of your experiment, then how would your results have been affected?