The correct answer is $\boxed{\text{B) 37.50}}$.
Rowan Premium Plan is a type of incentive plan in which workers are paid a base rate plus a premium for production above the standard. The premium is typically a percentage of the time saved.
In this case, the standard time is 20 hours and the time taken is 15 hours. This means that the worker produced 20/15 = 1.33 times the standard amount. The premium rate is 2/20 = 0.10, or 10%. Therefore, the total wages payable are 215 + 215*0.10 = 37.50.
Option A is incorrect because it is the total wages payable if the worker had produced the standard amount. Option C is incorrect because it is the total wages payable if the worker had produced 10% less than the standard amount. Option D is incorrect because it is not a valid option.