The equations below are linear equations of a system where a, b, and c are positive integers.
ay + bx = c
ay − bx = c
Which of the following describes the graph of at least 1 such system of equations in the standard (x,y) coordinate plane?

I. 2 parallel lines
II. 2 intersecting lines
III. A single line

  • A. I only

  • B. II only

  • C. III only

  • D. I or II only

  • E. I, II, or III