The question asks for the following: "In three-dimensional space, if each of the two lines L1 and L2 is perpendicular to line L3, which of the following must be true?"
(I.) L1 is parallel to L2
(II.) L1 is perpendicular to L2
(III.) L1 and L2 lie on the same place
The correct answer is E "none of the above"
. I chose a different answer at the start, because a few of these statements appeared very plausible. As suggested in the solution, am I supposed to always look for a statement that is sufficient to be true for these types of questions?