Just for clarity, could the wording in the question be changed a little? Like does it have to be a chord? I picked iii. because I thought a line could go through the middle and break apart somewhere in there so that now there's 2 lines that both touch the circle only once, but it turns out that wasn't exactly the answer. Thanks.
@TSS-Graviser That's interesting.... When you say a line that goes through the middle and breaks apart somewhere, do you mean something like this?
Technically a line has no endpoints (it goes on forever), so this line would eventually go on to intersect the circles at another point.
A chord is a line segment rather than a true line, because it has endpoints on the circle. So, in this way, it would be impossible for a chord to be also a tangent line.