Answer: Answer choice #4 (m is positive)
Step-by-step explanation:
[#1 is upper-left, #2 is upper right, #3 is lower left, and #4 is lower-right]
If the slope was m=0 then the line would be horizontal, and if the slope was undefined, then the line would be vertical. However, answer choice #1 and #3 have the incorrect answers and the correct answer is the answer for #3 and #1 respectively. This means that the answer to #1 is #3's answer and the answer to #3 is #1's answer. So neither have their correct answer.
The picture for both answer's #2 and #4 are the same. However, #2 says that the slope is negative, and #4 says that the slope is positive.
Let's take a loot at the picture for #2 and #4. It shows a line that is ascending diagonally to the right. A slope that is ascending right-way is a positive slope. This means that #2 is incorrect since it says that the picture has a negative slope, even though the slope ascends to the right. If #2 was correct, the picture would have a slope ascending to the left, but since it doesn't, it's wrong. Therefore, by process of elimination, the correct answer is choice #4: m is positive. Hope that this helps explain thoroughly enough!