

What are all the possible rays of this line?
As you can see, my answer was SQ with an arrow above it pointing to the left, and SR with an arrow above it pointing to the left. My understanding is that S must be included in every ray because it's at the end of the line. RQ with an arrow of the left would not be a solution because S is not included. But the book I'm using, Geometry: A Self-Teaching Guide, says that the solution is SQ with an arrow above it pointing to the left, and RQ with an arrow above it pointing to the left. Is the book wrong? Thanks.