Joani grows and sells tomatoes at a farmer’s market. She sells 2 pounds of tomatoes for $5.00, and 5 pounds of tomatoes for $12.50. If the relationship between the cost (y) and the number of pounds of tomatoes (x) is graphed on a coordinate plane, which ordered pair represents the unit rate? A
(0.4, 1)

B
(1, 2.5)

C
(2, 5)

D
(5, 12.5)