Answer: C. Lines m and n have the same slope so they are parallel.
Step-by-step explanation:
We know that the the slope(m) of a line passing through points (a,b) and (c,d) is 
Thus, the slope of line m passes through the points (4, 1) and (7, 3) will be

The slope of line n passes through the points (-3, 5) and (-9, 1) will be

Therefore, Lines m and n have the same slope and if slopes of two lines are same then they are parallel.
Hence, Lines m and n have the same slope so they are parallel.