The slope of a line is 0. what do you know about the line?

Your answer (C, the line is vertical) is correct

Your line would have to be horizontal. A vertical line yields an undefined slope.

Slope is rise over run. For a horizontal line you would have 0 rise and X amount of run or 0/x. 0 divided by anything = 0

For a vertical line, you would have the opposite, X rise and 0 run or x/0. You cannot divide by 0. It is impossible.

Therefore, your answer is the second option.

if you get paid hourly because if you get a salary you could work all week and only get paid a certain amount no matter how much you work but if you get paid hourly then you get paid for every minute you worked.