A shopkeeper buys 5 cartons for 105 rupees and 8 cartons for 155 rupees. If one carton has 5 items what is the average price per item?

A shopkeeper buys 5 cartons for 105 rupees and 8 cartons for 155 rupees. If one carton has 5 items what is the average price per item?
A: 4.20
B: 4.75
C: 4.50
D: None of these