Paul is comparing two high-speed Internet service providers (ISPs) for his business. The graph represents the cost of each ISP as a function of t, the duration in months of a service contract. A coordinate grid showing Internet Service Provider Cost, with Service Contract in months along the horizontal axis, and Total Cost in dollars along the y-axis. Two lines are graphed. One line is labeled I S P A and passes through (0, 180) and (12, 300). The second line is labeled I S P B and passes through (0, 0) and (12, 300).

If C(t) = 180 + 10t represents ISP A and C(t) = 25t represents ISP B, how long would the service contracts need to be for the total costs to be the same?

6 months
8 months
10 months
12 months