A certain strategy professor stands before a candy machine deciding among M&Ms, Reeses, and Twix. He likes M&Ms better than Reeses, and Reeses better than Twix. The cost of producing a candy bar and installing it in the machine is highest for Reeses, next highest for M&Ms, and lowest for Twix. All three candy bars are priced so that they have the same profit P-C if purchased. Which brands, if any, can you definitely say the professor will not buy? a) M&Ms b) Reeses c) Twix d) Indeterminate given the information supplied