c and a
by the way, thats easy. NO OFFENCE XD
Taking the same test right now....I think the answer is 4.5. Hope that helps!
The slope<span> of a horizontal </span>line<span>. A horizontal </span><span>line has slope 0
</span>
1:10 or 100:1000 so the point is to just add one zero to each side and you'll get it right