Answer:
Option C. Red grapes
Explanation:
we know that
The cost per pound is equal to the slope of the linear equation
so
For the red grapes
y=3x
the slope

For the green grapes
Find the slope
Observing the graph
For x=1, y=2
Is a direct variation (the line pass through the origin)
so
m=y/x
substitute

Compare

therefore
The red grapes cost more per pound