For the given data on minutes and total cost, identify the dependent variable and determine which option represents a direct proportion.

The table and graph show "Minutes" and "Total Cost (R)".

The total cost depends on the number of minutes used.
The dependent variable for this data is the $\boxed{\text{Total Cost (R)}}$.

A direct proportion relationship is represented by a straight line that passes through the origin $(0,0)$.

Option A starts at a cost of R180 for 0 minutes, so it does not pass through the origin.
Option B starts at a cost of R0 for 0 minutes and shows a linear increase.
Option B represents a direct proportion relationship.
Reason: $\boxed{\text{Option B}}$ represents a direct proportion because its graph is a straight line that passes through the origin $(0,0)$, meaning the cost is R0 when 0 minutes are used, and the cost increases proportionally with the minutes used.