Phone calls cost £ y
for
x
minutes.

The graph gives the values of
y
for values of
x
from 0 to 5.

(a)(ii) Give an interpretation of the gradient of the graph.

A - £0.50
B - The increase in price each minute.
C - The fixed charge for the call.
D - The number of minutes per £1 cost.
E - The length of the call when the charge is £0.