Answer: B. Likely to cost you less in the long run.
Cheaper motor oils tend to get dirtier faster than the expensive motor oils. The number of times that you're going to change your motor oil when using the cheaper motor oil will be way more in the long run.
Most of the expensive motor oils tend to be cleaner and more efficient. Yes they are more expensive, but the number of times you will need to change the motor oil will be likely cut in half compared to cheaper motor oils and they are definitely better for you engines.