Answer:3 lines could be used
Explanation:
You need 2 points to draw a line. The order doesn't really matter. Line AB is the same as line BA. The problem is to select 2 points out of 3 to draw different lines. If we do the same to the others, we get the following pairs of points to draw lines.
AB , AC
BA , BC
CA , CB
which is only 3 lines