The formula for finding the slope of a line is y= rise/run.
Using this information, we can plug in the numbers given on the image.
The slope of the blue triangle would be 2(rise)/2(run), which simplifies to 1/1=1.
The slope of the red triangle would be 1(rise)/1(run), which simplifies to 1/1=1.
Seeing as the slopes are equal, the answer choice is C.