what must two lines have the same if they are parallel?

Question

a x intercept
b y intercept
c slope
d length

Answer 1

It has to be C. slope. They will never intercept so it can't be A. or B. They can be parallel and be different lengths so it must be slope.◙

Answer 2

If I remember my algebra, it must be D. length. It cannot be the A & B since they are intercepts and parallel lines will never intercept. It may or may not have a slope since the slope of a line measures the steepness of the line. So, it is not necessary to have C. slope. By its very defintion, a line must have length, as the answer is D.