Which statement is correct?

A horizontal line has no slope

A vertical line has a slope of zero

A line that rises from left to right has a positive slope

A line that falls right to left has a negative slope

A line that rises from left to right is positive is the answer.

A vertical line has an infinite slope.

A horizontal line has a slope of zero.

And a line that falls from right to left is a positive line, you're just reading it backwards